build.sh will build a docker image for ubuntu-2204 with amd64 architecture. If you are using an ARM architecture do set the --platform option as in build.sh and run it with the --platform option in runit.sh.
Otherwise you can remove these options.
runit.sh creates a docker container from the built image, and executes the file execthis.sh in the docker container and copies all files inside the current directory, under a subdirectory named home/.