To get started with Android/LineageOS, you'll need to get familiar with Source Control Tools.
To initialize your local repository using the LineageOS trees, use a command like this:
repo init -u https://github.com/SoulAOSP/android.git -b lineage-23.2 --git-lfs
Then to sync up:
repo sync -c -j$(nproc --all) --force-sync --no-clone-bundle --no-tags --optimized-fetch --prune
. build/envsetup.sh
brunch devicecodename
Please see the LineageOS Wiki for building instructions, by device.