How to build a Home Cinema?

I already wrote here a thread but i dont know why it is gone.
I search for a good How to to build my own cinema in my cellar.
Hope yoou can give me hints or advice.
Greetings
Leifu

something like this started here.

https://www.digitalworldz.co.uk/av-home-cinema-5/295857-floating-wall-av.html?highlight=false+wall