To get started with Android/SpringOS, you'll need to get familiar with Source Control Tools.
repo init --depth=1 -u https://github.com/Magnus-OS/android.git -b 11 --git-lfs
Then to sync up:
repo sync
You can use your LineageOS trees to build MagnusOS without any changes in 3 simple steps.
. build/envsetup.sh
lunch lineage_<devicecodename>-userdebug
mka bacon