Server side : PHP libs and utils
To consult all PHP librairies methods and utils, just go there : PHP docs

Client side : JS libs
To consult all JS librairies methods, it's here : JS docs

Manual installation, Instance usage, Module creation and global training
Training, concepts, main informations needed to understand how to use it ? : The main documentation and training

Various environnement and helPHP installation
Before running it you can need different environnement depending your needs, here are some scripts to help you : helPHP env install repository

The other repository :
Not really a documentation, but you'll need it so... to gain some time :
helPHP main repository
helPHP basic instance repository