Download platform-tools and extract the folder somewhere, then open CMD as an administrator.
It is recommended to keep this window open and use it throughout the entire guide.
Replace
path\to\platform-toolswith the actual path to the platform-tools folder, for example C:\platform-tools.
cd path\to\platform-toolsReplace
path\to\moddedtwrp.imgwith the actual path of the image
fastboot boot path\to\moddedtwrp.imgadb shell format