Request for assistance please room treatment

I do have it treated now, but I don't think it's correct. I need to treat it properly. I've tried a multitude of different positions, absorption, diffusion, trapping, etc. and my walls are starting to look like swiss cheese. I'm at the point now where I need to strip the room, putty, sand, and paint. But when I re-install the room treatments, they have to go in the correct position the first time. This is where your assistance comes in. I've tried many different web sites and so on, but it all seems best guess. I'm hoping to lean upon your "experience".
My room is 22'long, 11'wide, and 7'4" high, and is in a finished concrete basement. I look forward to reading your suggestions.
Thank You.