Basic Classes

I am trying to design some custom code for my IPS installment, and instead of trying to use old-fashioned php queries like the code I am migrating uses, I'd like to use build in IPS classes, much like the following (Found here: https://invisionpower.com/4docs/advanced-usage/development/working-with-members-r179/)

\IPS\Member::load( 1 );

I cannot find a list of these classes or solid documentation. I came from vBulletin through XenForo, and VB always  had extensive documentation. Is this located anywhere for IPS?