Wiring 5.3 into factory bulk head. HELP!

[faun_cee]

I used a 2001 tahoe for a donor vehicle and took everything needed.
My Problem is I don't understand how to integrate the wiring harness/fusebox from the tahoe into the bulkhead of the 69.

this is my first swap for any type of vehicle so all the terminology is still a bit confusing. ive been looking for a thread or video that dummy proofs it for me. im frustrated with this and i am at my last resort