building the source

What you should have:

BASH (on WSL or on a real *nix or *BSD machine)

git

qemu-i386

Actual building

Here's what I suggest:

$ git clone https://github.com/Platypus-Tech/new-platypus-os-drafts

$ ./clean.sh

$ ./headers.sh

$ ./iso.sh

$ ./qemu.sh

This code will execute in QEMU. I suggest you read it just to know what it does.