firstly, make sure to pull git-lfs references with: :git lfs fetch origin main:
install cmake and sdl2-dev packages in manner suitable to your distribution
add /tools/ directory to your $PATH, for example, with :source hooks:
navigate to one of /apps/ folders for demos
run `twn build` to build
runnable apps should have the same name as app folder it is in

with windows it's assumed you have bash and gnu software
you might also want to install python3, but it's not a hard requirement