The integrations don’t follow a simple template or tutorial, each one is different. I’ve done a WaveWorks, HBAO+, and a partial volumetric lighting integration and each one is completely different from the other.
HBAO+ is definitely the easiest of the bunch, that said there have been improvements made to the HBAO+ implementation (it’s at v3 now – I think the VXGI and HBAO+ branches both still use v2) and it took me a solid day to integrate the updated API and functionality into my UE4 fork despite already having most of it already integrated.