A:Answer Hello, assuming you are looking to create a home theater with 5.1 surround sound minimum...(if not disregard) you need:
1. AVR (Audio Video Receiver- 4k capable Denon with audyssey is good for the price)
2 Front, center channel, sub woofer and 2 rear channel speakers 2. Long HDMI cable to connect the projector to the AVR monitor output....I wired mine into the room behind sheet rock
3. Some kind of HDMI stream media stick like the Roku, Chromecast, Amazon Firestick....look for something that you can stream media from your computer and phone to your the stick.....and one that has the ability to do voice recognition (They will listen your your conversations that are going on in your house so that sucks) or has a keyboard so you can enter search terms
Hope that helps