My place is infested with them, so, unfortunately, I'm getting lots of unwanted experience in this situation.
First, get a good wire cage trap. I got mine from Tractor Supply. It needs to be SOLID because ground hogs are very strong and will bend a cheap trap.
Next, figure out where he lives. If he hangs out in the hole under the house, wait until he goes in there and then set up the trap in front of the hole. Doesn't have to be real close, several feet away is OK.
Then, set up a couple of boards on end to form a chute to direct the animal to the trap. You would think he would just climb over, but they don't. They are lazy and creatures of habit, so he will just follow along the boards until he gets to the trap and will walk right in.
Use something sweet for bait. Ones around my house like apples and carrots. Throw a couple of concrete blocks on top of the trap to hold it down as they don't like walking into a trap that is moving around.
Once in the trap, relocate to the place of choice. Watch your fingers when handling the trap, they have long front teeth and will bite you through the cage if you get your hand up against it.