ποΈ Building on Windows
Install Git
ποΈ Building on macOS
Installing Homebrew
ποΈ Building on Linux
I (Null) don't use Linux for development but I was able to get Matrix OS to build on Linux via WSL and Github Action.
ποΈ Build via Github Action
Matrix OS Github repo has Github Action enabled that builds Matrix OS on every commit. If you just want to do a simple change to Matrix OS without wanting to set up the tool chain. You can simply fork the Matrix OS repo and then commit your changes there. You will be able to download the compiled firmware as an Action Artifact. (The firmware will be compiled under nightly mode)