Getting and keeping contact

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Drive your shoulders to your hips and sit up tall. If you have a strong core your horse cannot pull you anywhere. Keep your fore-arms soft and your upper arms as part of your upper body.
Lunge lessons will help you get a better core balance and regular lessons with a good dressage trainer will help you with your hands.

Good luck!

That's odd. He looks very uncomfortable? Have you tried other bits? I'd take the flash off and let him stand around until he was still. I don't think it's normal to keep fussing. Most colts quiet after just a few minutes, even the first time they're bitted. I think he has to learn to carry the bit before you can start contact.

Do you know who trained your horse? I've seen horses start developing that kind of nervous habbit when they are stressed and forced into a frame. Even if there is no contact at all they're trying to evade it.
I would try to ride forward make sure your horse is never ever behind the vertical and ask him to reach high and low. Keep him occupide so that his mind isn't on fiddeling. Try to get him to "play" with the bit on your terms.
It won't help to crank a flash on him. Gaggets NEVER salve a problem. You need a good trainer to be able to fix problems...
Good luck!