To build PureNexus from source, you'll need to be familiar with Git and Repo.
To initialize your local repository, use this command:
repo init -u https://github.com/UBERPureNexus/manifest.git -b lp
Then to sync source, use this command:
repo sync
After syncing is done, use these commands to build:
For UserDebug Builds
1.) . build/envsetup.sh
2.) brunch xxxx xxxx= device name aka shamu
For User Builds
1.) . build/envsetup.sh
2.) breakfast
3.) Pick Device
4.) mka bacon
Enjoy, Stick around for a while AOSP Building is Fun!!!