diff --git a/BuildWindowsRelease.sh b/BuildWindowsRelease.sh
index ef295b0..88e2594 100644
--- a/BuildWindowsRelease.sh
+++ b/BuildWindowsRelease.sh
@@ -208,7 +208,7 @@ make -f Makefile.omdev.mingw omsimulator
 # build the installer
 cd /c/dev/${OM_ENCRYPT}OM${PLATFORM}/OMSetup
 rm -rf 	OMLibraries.nsh
-if ! makensis //MSYSRUNTIME="${MSYSRUNTIME}" //DPLATFORMVERSION="${PLATFORM::-3}" //DOMVERSION="${REVISION_SHORT}" //DPRODUCTVERSION=${PRODUCT_VERSION} OpenModelicaSetup.nsi > trace.txt 2>&1 ; then
+if ! makensis //DMSYSRUNTIME="${MSYSRUNTIME}" //DPLATFORMVERSION="${PLATFORM::-3}" //DOMVERSION="${REVISION_SHORT}" //DPRODUCTVERSION=${PRODUCT_VERSION} //DOPENMODELICASOURCEDIR=/c/dev/${OM_ENCRYPT}OM${PLATFORM} //DOPENMODELICAHOME="${OPENMODELICAHOME}" OpenModelicaSetup.nsi > trace.txt 2>&1 ; then
   cat trace.txt
   exit 1
 fi
diff --git a/OpenModelicaSetup.nsi b/OpenModelicaSetup.nsi
index 336c5bf..3debdd5 100644
--- a/OpenModelicaSetup.nsi
+++ b/OpenModelicaSetup.nsi
@@ -4,7 +4,7 @@
 Unicode true
 
 !ifndef MSYSRUNTIME
-  !error "Argument MSYSRUNTIME is not set. Call with argument /MSYSRUNTIME=mingw32|mingw64|ucrt64"
+  !error "Argument MSYSRUNTIME is not set. Call with argument /MSYSRUNTIME=mingw|ucrt"
 !endif
 
 !ifndef PLATFORMVERSION
@@ -19,6 +19,14 @@ Unicode true
   !error "Argument PRODUCTVERSION is not set. Call with argument /DPRODUCTVERSION=OpenModelica version"
 !endif
 
+!ifndef OPENMODELICASOURCEDIR
+  !error "Argument OPENMODELICASOURCEDIR is not set. Call with argument /DOPENMODELICASOURCEDIR=c:\path\to\OpenModelica"
+!endif
+
+!ifndef OPENMODELICAHOME
+  !error "Argument OPENMODELICAHOME is not set. Call with argument /DOPENMODELICAHOME=c:\path\to\OpenModelica\build_cmake\install_cmake"
+!endif
+
 Name OpenModelica${OMVERSION}-${PLATFORMVERSION}bit
 
 # General Symbol Definitions
@@ -118,10 +126,10 @@ Section "OpenModelica Core" Section1
   SetOverwrite on
   # Create bin directory and copy files in it
   SetOutPath "\\?\$INSTDIR\bin"
-  File "..\build\bin\*"
-  File "..\OSMC-License.txt"
+  File "${OPENMODELICAHOME}\bin\*"
+  File "${OPENMODELICASOURCEDIR}\OSMC-License.txt"
   # Copy the openssl binaries
-!if ${PLATFORMVERSION} == "32"
+!if PLATFORMVERSION == "32"
   File "bin\32bit\libeay32.dll"
   File "bin\32bit\libssl32.dll"
   File "bin\32bit\ssleay32.dll"
@@ -137,33 +145,37 @@ Section "OpenModelica Core" Section1
   File /r /x "*.svn" "$%OMDEV%\tools\msys\${MSYSRUNTIME}${PLATFORMVERSION}\bin\osgPlugins-3.6.5\*"
   # Create bin\ffi directory and copy files in it
   SetOutPath "\\?\$INSTDIR\bin\ffi"
-  File "..\build\bin\ffi\*"
-!if /FILEEXISTS "..\build\bin\omc-semla\*.*"
+  File "${OPENMODELICAHOME}\bin\ffi\*"
+!if /FILEEXISTS "${OPENMODELICAHOME}\bin\omc-semla\*.*"
   # Create bin\omc-semla directory and copy files in it
   SetOutPath "\\?\$INSTDIR\bin\omc-semla"
-  File /r "..\build\bin\omc-semla\*"
+  File /r "${OPENMODELICAHOME}\bin\omc-semla\*"
 !endif
   # Create icons directory and copy files in it
   SetOutPath "\\?\$INSTDIR\icons"
   File /r /x "*.svn" "icons\*"
-  File "..\OMEdit\OMEditLIB\Resources\icons\omedit.ico"
-  File "..\OMOptim\OMOptim\GUI\Resources\omoptim.ico"
-  File "..\OMPlot\OMPlot\OMPlotGUI\Resources\icons\omplot.ico"
-  File "..\OMShell\OMShell\OMShellGUI\Resources\omshell.ico"
-  File "..\OMNotebook\OMNotebook\OMNotebookGUI\Resources\OMNotebook_icon.ico"
+  File "${OPENMODELICASOURCEDIR}\OMEdit\OMEditLIB\Resources\icons\omedit.ico"
+  File "${OPENMODELICASOURCEDIR}\OMOptim\OMOptim\GUI\Resources\omoptim.ico"
+  File "${OPENMODELICASOURCEDIR}\OMPlot\OMPlot\OMPlotGUI\Resources\icons\omplot.ico"
+  File "${OPENMODELICASOURCEDIR}\OMShell\OMShell\OMShellGUI\Resources\omshell.ico"
+  File "${OPENMODELICASOURCEDIR}\OMNotebook\OMNotebook\OMNotebookGUI\Resources\OMNotebook_icon.ico"
   # Create include\omc directory and copy files in it
   SetOutPath "\\?\$INSTDIR\include\omc"
-  File /r /x "*.svn" "..\build\include\omc\*"
+  File /r /x "*.svn" "${OPENMODELICAHOME}\include\omc\*"
   # Create lib\omc directory and copy files in it
   SetOutPath "\\?\$INSTDIR\lib\omc"
-  File /r /x "*.svn" /x "*.git" "..\build\lib\omc\*"
+  File /r /x "*.svn" /x "*.git" "${OPENMODELICAHOME}\lib\omc\*"
+!if /FILEEXISTS "${OPENMODELICAHOME}\lib\python\*"
   # Create lib\python directory and copy files in it
   SetOutPath "\\?\$INSTDIR\lib\python"
-  File /r /x "*.svn" /x "*.git" "..\build\lib\python\*"
+  File /r /x "*.svn" /x "*.git" "${OPENMODELICAHOME}\lib\python\*"
+!endif
   # Create tools directory and copy files in it
   SetOutPath "\\?\$INSTDIR\tools"
   # copy the setup file / readme
+!if /FILEEXISTS "$%OMDEV%\tools\MSYS_SETUP.bat"
   File "$%OMDEV%\tools\MSYS_SETUP*"
+!endif
   # Create msys directory and copy files in it
   SetOutPath "\\?\$INSTDIR\tools\msys"
 !if ${PLATFORMVERSION} == "32"
@@ -185,8 +197,8 @@ Section "OpenModelica Core" Section1
       /x "osgVolume" /x "osgWidget" /x "clang-cl.exe" /x "clang-check.exe" /x "llvm-lto2.exe" /x "doc" \
       "$%OMDEV%\tools\msys\*"
 !else #64 bit
-!if ${MSYSTEM} == "ucrt"
-  File /r /x "mingw32" /x "mingw64" /x "clang64" /x "clang32" /x "group" /x "passwd" /x "pacman.log" /x "tmp\*.*" /x "*.pyc" /x "libQt5*.*" \
+!if ${MSYSRUNTIME} == "ucrt"
+  File /r /x "mingw32" /x "mingw64" /x "mingw*.*" /x "clang64" /x "clang32" /x "clang*.*" /x "group" /x "passwd" /x "pacman.log" /x "tmp" /x "home" /x "*.pyc" /x "libQt5*.*" \
       /x "moc.exe" /x "qt*.qch" /x "Qt5*.dll" /x "libwx*.*" /x "libgtk*.*" /x "qtcreator" /x "rcc.exe" \
       /x "testcon.exe" /x "libsicu*.*" /x "libicu*.*" /x "wx*.dll" /x "libosg*.*" /x "Adwaita" /x "OpenSceneGraph" /x "gtk-doc" \
       /x "poppler" /x "man" /x "libdbus.*" /x "tcl*.*" /x "avcodec*.*" /x "windeployqt.exe" /x "python3.5" /x "mingw_osg*.*" \
@@ -204,7 +216,7 @@ Section "OpenModelica Core" Section1
       /x "osgVolume" /x "osgWidget" /x "clang-cl.exe" /x "clang-check.exe" /x "llvm-lto2.exe" /x "doc" \
       "$%OMDEV%\tools\msys\*"
 !else # mingw64
-  File /r /x "mingw32" /x "ucrt64" /x "clang64" /x "clang32" /x "group" /x "passwd" /x "pacman.log" /x "tmp\*.*" /x "*.pyc" /x "libQt5*.*" \
+  File /r /x "mingw32" /x "mingw32.*" /x "ucrt64" /x "ucrt64.*" /x "clang64" /x "clang32" /x "clang*.*"  /x "group" /x "passwd" /x "pacman.log" /x "tmp" /x "home" /x "*.pyc" /x "libQt5*.*" \
       /x "moc.exe" /x "qt*.qch" /x "Qt5*.dll" /x "libwx*.*" /x "libgtk*.*" /x "qtcreator" /x "rcc.exe" \
       /x "testcon.exe" /x "libsicu*.*" /x "libicu*.*" /x "wx*.dll" /x "libosg*.*" /x "Adwaita" /x "OpenSceneGraph" /x "gtk-doc" \
       /x "poppler" /x "man" /x "libdbus.*" /x "tcl*.*" /x "avcodec*.*" /x "windeployqt.exe" /x "python3.5" /x "mingw_osg*.*" \
@@ -225,14 +237,14 @@ Section "OpenModelica Core" Section1
 !endif
   # Create share directory and copy files in it
   SetOutPath "\\?\$INSTDIR\share"
-  File /r /x "*.svn" /x "*.git" "..\build\share\*"
+  File /r /x "*.svn" /x "*.git" "${OPENMODELICAHOME}\share\*"
   # Copy the OpenModelica web page & users guide url shortcut
   SetOutPath "\\?\$INSTDIR\share\doc\omc"
-  File "..\doc\OpenModelica Project Online.url"
-  File "..\doc\OpenModelicaUsersGuide.url"
+  File "${OPENMODELICASOURCEDIR}\doc\OpenModelica Project Online.url"
+  File "${OPENMODELICASOURCEDIR}\doc\OpenModelicaUsersGuide.url"
   # Copy OMSens directory
   SetOutPath "\\?\$INSTDIR\share\OMSens"
-  File /r /x ".git*" "..\build\share\OMSens\*"
+  File /r /x ".git*" "${OPENMODELICAHOME}\share\OMSens\*"
 SectionEnd
 
 Section -Main SEC0000
@@ -282,7 +294,7 @@ Section -post SEC0001
   Rename "$INSTDIR\tools\msys\mingw32\bin\libeay32.dll" "$INSTDIR\tools\msys\mingw32\bin\libeay32-O.dll"
   Rename "$INSTDIR\tools\msys\mingw32\bin\ssleay32.dll" "$INSTDIR\tools\msys\mingw32\bin\ssleay32-O.dll"
 !else # mingw64 or ucrt64
-!if ${MSYSTEM} == "mingw"
+!if ${MSYSRUNTIME} == "mingw"
   Rename "$INSTDIR\tools\msys\mingw64\bin\libeay32.dll" "$INSTDIR\tools\msys\mingw64\bin\libeay32-O.dll"
   Rename "$INSTDIR\tools\msys\mingw64\bin\ssleay32.dll" "$INSTDIR\tools\msys\mingw64\bin\ssleay32-O.dll"
 !endif
diff --git a/README.md b/README.md
index b06b0cd..5f3c103 100644
--- a/README.md
+++ b/README.md
@@ -4,7 +4,89 @@ OpenModelica Windows installer based on [NSIS](https://nsis.sourceforge.io/Main_
 
 ## Dependencies
 
-- [NSIS](https://nsis.sourceforge.io/Main_Page)
+  - [NSIS 3.0.4](https://nsis.sourceforge.io/Main_Page)
+    - Copy `AccessControlW.dll` into your NSIS plugin directory, e.g. into
+      `C:\Program Files (x86)\NSIS\Plugins\x86-unicode`.
+  - [git](https://git-scm.com/)
+  - [OMDev](https://gitlab.liu.se/OpenModelica/OMDevUCRT)
+  - (optional) [SignTool](https://learn.microsoft.com/en-us/windows/win32/seccrypto/signtool),
+    part of
+    [Microsoft Windows Software Development Kit](https://developer.microsoft.com/en-us/windows/downloads/windows-sdk/).
+
+## Build Windows installer
+
+### Environment variables
+
+You'll need to export all tools to `PATH` environment variable in your MSYS2 UCRT64 shell
+`%OMDEV%\tools\msys\ucrt64.exe`:
+
+```bash
+export PATH=$PATH:/c/Program\ Files/Git/bin
+export PATH=$PATH:/c/Program\ Files\ \(x86\)/NSIS/Bin
+```
+
+Also make sure to set environment variables
+
+  - `OMDEV`, e.g. `c:\\OMDev`
+  - `OPENMODELICAHOME`, e.g. `d:\\path\\to\\OpenModelica\\build_cmake\\install_cmake`
+  - `OPENMODELICALIBRARY`, e.g. `d:\\path\\to\\OpenModelica\\build_cmake\\install_cmake\\lib\\omlibrary`
+
+with Windows style paths using `\`.
+
+Build:
+
+  - OpenModelica
+  - OpenModelica libraries
+  - OMPython
+  - OMSimulator
+  - OMSens
+
+Download the the HTML and PDF versions of OpenModelica User's Guide:
+
+```bash
+cd ${OPENMODELICAHOME}/share/doc/omc
+wget --no-check-certificate https://openmodelica.org/doc/openmodelica-doc-latest.tar.xz
+tar -xJf openmodelica-doc-latest.tar.xz --strip-components=2
+rm openmodelica-doc-latest.tar.xz
+wget --no-check-certificate https://openmodelica.org/doc/OpenModelicaUsersGuide/OpenModelicaUsersGuide-latest.pdf
+```
+
+## Run NSIS
+
+Start `%OMDEV%\tools\msys\ucrt64.exe` or `%OMDEV%\tools\msys\mingw64.exe` and run:
+
+```bash
+export PLATFORM="64"        # 64 or 32 bit
+export MSYSRUNTIME="ucrt"   # ucrt or mingw
+export OPENMODELICA_SOURCE_DIR="d:\\path\\to\\OpenModelica"
+export REVISION_SHORT=`cd $OPENMODELICA_SOURCE_DIR; git describe --match "v*.*" --always --abbrev=0`
+export PRODUCT_VERSION="${REVISION_SHORT:1}"
+# make a valid VIProductVersion by stripping everything after "-"
+BEGIN=${PRODUCT_VERSION/-*/}
+PRODUCT_VERSION=${PRODUCT_VERSION::${#BEGIN}}
+PRODUCT_VERSION=${PRODUCT_VERSION}.0
+
+makensis //DMSYSRUNTIME="${MSYSRUNTIME}" \
+         //DPLATFORMVERSION="${PLATFORM}" \
+         //DOMVERSION="${REVISION_SHORT}" \
+         //DPRODUCTVERSION="${PRODUCT_VERSION}" \
+         //DOPENMODELICASOURCEDIR="${OPENMODELICA_SOURCE_DIR}" \
+         //DOPENMODELICAHOME="${OPENMODELICAHOME}" \
+         OpenModelicaSetup.nsi
+```
+
+> [!NOTE]
+> `PRODUCT_VERSION` needs to be in `X.X.X.X` format.
+
+## Optional: Sign the installer
+
+To sign the installer you'll need a code-signing certificate (SPC).
+See the [doc for more information](https://learn.microsoft.com/en-us/dotnet/framework/tools/signtool-exe).
+
+```bash
+export SIGNTOOL=`find /c/Program\ Files\ \(x86\)/Windows\ Kits/10/ -wholename "*${XPREFIX}/signtool.exe" | tail -1`
+"${SIGNTOOL}" sign /n "Me" /f MySPC.pfx /tr "http://timestamp.globalsign.com/tsa/r6advanced1" /a /td SHA256 /v OpenModelica.exe
+```
 
 ## Bug Reports