Start by staking the dog out on a three-foot chain and letting him rear up, roll and fight restraint on his own time. If you're not there to become annoyed, or worse, offer sympathy to reinforce his fears, he quickly learns on his own that restraint is not life-threatening. Next, make a 50-foot check cord using stiff rope. Limp cords are always tangling, and short ones don't provide enough freedom while the dog is learning to quarter back and forth. When he looks back at you, call the name as you drop to one knee.
Dogs see that as a play invitation, and most come running.
If yours doesn't, scratch at the ground like a dog digging a bone. When he arrives to see what you've found, be ready with a reward of meat, skin or steak fat. Repeat name training a couple of times, and then try calling without kneeling. But always praise and pet. That's where the headcollar excels.