To initialize your local repository, use this command:
repo init -u https://github.com/CerberusOS/manifest.git -b Pie
Then to sync, use this command:
repo sync -c -j8 --force-sync --no-clone-bundle --no-tags
After download CerberusOS source now you able to build rom by type
. build/envsetup.sh
lunch cerberus_CODENAME-userdebug
Then to start build
mka cerberus