The H8000FW is a sophisticated and complex unit, which is not for everyone. In particular, the routing arrangements can prove hard to understand.

If the User Manual is not helpful, I would suggest you try the H8000 Routing Utility, which gives a more visual representation.

https://www.eventideaudio.com/support/product/671/installers

Alternatively you could try the Factory Routings, such as "ADAT 8 Track A,B".