start small with defined goals - easier for you and you'll have specific questions that will elicit better responses.
A couple of things:
1) running computers through AVRs can make things "interesting"-especially if you're just starting out. I'd make sure the computers work properly connected directly to your TV before routing them through your receiver (if it will function that way)
2) Build up one app at a time. Tough enough to troubleshoot anyway w/o having to deal with complexity and not knowing which app/connection might be causing the problem
As the others have said-this is really a hobby and you just have to dive in and read and experiment a bit. Frustrating at times? Heck yeah, but there's no substitute for personal experience. The learning curve can be steep, but you can't bypass it with a simple "I've got a bunch of stuff and want someone to tell me how to hook it up" post...