Here’s a link to some good information. There’s a free interactive 3D design tool near the bottom of the page. It is a good idea to think through all the details and plan everything for a great theater experience. There is a lot to consider, but with patience and the desire to learn, you will be rewarded. This forum is a great place to ask questions. There are a lot of very knowledgeable folks here that like to help.
Best design practices
You haven’t given us the details for your room yet. Dimensions, number of seats, budget, etc.