First, you need a connection from TV audio out, to Surround Sound audio in. This will often be a cable with RCA Phono connectors such as you might find on any stereo. They typically have red and white color coded connectors. If the cable also supports video, there will be a 3rd, yellow connector. You'll have to look at the back of the TV and back of the surround sound to see if there's a cable in place. If you use a 3 wire cable, you can just leave the yellow connector hanging loose at each end. Some of the TVs don't have RCA phono jack outputs, and people have used 1/8" headphone jacks as the audio source. If that's your situation, you'll have to get a different cable, but they're not hard to find.
Second, the surround sound input needs to be set to use the audio coming from this cable. Often, that'll be a setting called AUX, but it's going to vary by device. The user guide will identify this.
Third, some TVs will always send audio out over these wires, but others have to have audio out selected on the TV menu. Again, the user guide for the TV will help figure this out.
After getting it set up, you will still have to turn on both the surround sound and the TV in order to get what you want. As long as you don't change the settings, that'll probably be all that's required from that point on.