First off, you'll need a terminal one way or another.
Make sure to use my fork of PSn00bSDK because if you dont psp and other emulators wont work (ps1 and duckstation will work) Follow the PSn00bSDK set up instructions here https://github.com/UNSTOP4BLE/PSn00bSDK-kuseg/blob/kuseg/doc/installation.md (set up mingw)
Also you need to install python in mingw (pacman -S mingw-w64-x86_64-python), install pip and install the python PIL library (pip install PIL)
You also need to install ffmpeg, libavformat and libswscale.
First, make sure to cd to the repo directory where the CMakeLists.txt is. You're gonna want to run a few commands from here;
this will build the tools.
cmake -S ./tools -B ./tools/build -G "Ninja"
cmake --build ./tools/build
this builds the game itself.
cmake -S . -B ./build -G "Ninja" -DCMAKE_TOOLCHAIN_FILE=C:\PSn00bSDK\lib\libpsn00b\cmake\sdk.cmake Replace C:\PSn00bSDK with the path you put PSn00bSDK in.
(add -DCMAKE_BUILD_TYPE=Debug at the end to build for debug mode)
cmake --build ./build
You can read more about the asset formats in FORMATS.md
If everything went well, you should have a funkin.bin and a funkin.cue in the build directory.