He just takes a few quick trot steps sometimes, but that comes with experience, and he's still young yet.
As for the head set, I'd recomend doing some bending and latteral excersises. Things like leg yeild (not sidepass, still moving forward), taking his head (and eventually front end) to the inside and the outside while keeping his haunches on the rail. This helps loosen their back and relax so they feel more ready to collect. There are suppling excersises you can to too. I don't know how much he knows, but this is the basics. Try , first while standing, take the rein and hold him, wiggling your fingers. When he drops his head to get away from the pressure, imediatly give your hand. Try this at walk and jog too and eventually lope. You can also give a series of half halts until he drops. Most horses after theyve gone round will stretch down after. These will help you when you go tot shows too. The bending especially. Don't be afraid to take rein. He doesn't want you to touch his mouth, but you have to teach him that if he doesn't keep it down, you will be touching it. When he's getting distracted in the warm up ring, do a LOT of bending and leg yeild, kkeep him BUSY. Never do more than a lap just going on the rail. It's also helpful to bring him to as many new places as possible so he soon gets used to being riden away from home. Young horses are tricky this way, but if you can expose him to as many different places as possible now, and work him like you would at home (consistancy is key when something changes), you'll have it much easier later.