Here's a link to a map. It opens at the Tenaya Lk trail head. Take the trail south, follow it, and then take a left so you skip Clouds Rest.

elevation ascending estimate:
going: 2800'
returning: 2200'
Actually that is a low estimate. I left out the undulating sections of the trail.

People often hike Clouds Rest on that trail. I think it's 5 miles one way. Half Dome adds 3-4 more. Remember, you need a HD cables permit to make the climb. There is a last-minute lottery for about 50 of those 36 hours before the climb on Recreation.gov