Not tech savvy - how do I hard-wire Plex to my A/V system?

I have been starting to get Plex set up and have been streaming movies over my Wifi, but I have to downgrade the quality to 4MB/720p to get Blu-Ray movies to play. I'm thinking if I can hard-wire my system and bypass the Wifi it would work better, but I'm not sure. This is what I have so far: 1. Plex server on a 2011 MacBook Pro 2. All of the movies are on a USB external hard drive, connected to the MacBook Pro 3. Yamaha RX-V577 Receiver (Wifi enabled, has HDMI inputs and an ethernet jack, but I don't know what that's for) 4. Vizio M602i-B3 TV 5. Chromecast 6. PS3 7. XBox 360 8. Wii

I've tried using the iPad Plex app to stream through the Chromecast, which is connected to the receiver. I've also tried the Plex PS3 app. In both cases I had to downgrade the quality to get some movies to play. Is it possible to hardwire to my receiver or TV? Would the MacBook Pro be connected to the receiver since that's where the Plex server is, or just the external hard drive? What cable would I use to connect it? I'm a little lost.

Submitted by FreeRangeOtter Xbox 720 Release Date 2015