Initially, I ran an HDMI cable from my laptop to the TV, and watched the ride on the TV while I pedaled.
But I quickly grew bored with having only the Zwift app to cut the tedium of riding on a trainer. Now I have a DVD player attached to the TV, and watch old TV shows (e.g., "Star Trek: The Next Generation") while I ride (streaming would do just as well), with my laptop on a stool below the TV (so I can see when I'm changing slope and shift accordingly).
Mark