Well, that depends on what you are using for your gaming. If you are using something like a Nintendo 3DS, a PS4, an Xbox One, an Xbox 360, or a PS3 there should be RCA connectors (3 - red, white, and yellow) or on the higher end consoles even an HDMI port, simply plug the cables into the corresponding female connectors on the console and on the back of your TEAC. If you have an HDMI output on your console, get an HDMI cable and plug that in (your TEAC has 3HDMI ports).
Once you have done this, take the TV remote and click "Setup." This will take you to the "Source" screen. In the 3rd section down, you should see HDMI1, HDMI2, HDMI3, and PC. The choice you make here depends on which HDMI port you used for gaming. Choose that one and click the "OK" button on your remote. If you hooked it up correctly, you should see something on the screen relating to your gaming console. If you do, then start playing your game!
If you don't want to or can't use the HDMI ports, your other option is to use the RCA ports. These are colored, usually, red, white, and a third color. Plug the red and white connectors into the corresponding connectors and place the last color (yellow, green, etc.) into the last connector. Follow the above Setup procedure except for choosing the Input. In this case, I believe you should choose the YPbPr input.
If you are using a computer for gaming, you must use an HDMI port. The Setup procedure is the same for setting up a gaming console.
Happy gaming!