I watched others and learned by internet directions, I don't know if it's exactly considered join up.. but let me explain.
Mister would try to walk over me if I wanted him to stand, or he would paw the ground when standing for any length of time, he was also very mouthy and did start to grab at me on occasion. His former owner would hand feed him.. I don't do that at all. I either give treat on the ground or in his grain bucket. Plus working with him in the roundpen has greatly improved his manners.
(If you don't have a roundpen, using a lunge line and long whip is fine too..just don't hurt them with the whip, you want light contact)
I took him in the roundpen, without his halter and with a long rope rolled up tossed it at him landing on or near his hindquarters, once he moved, I kept following him around my eyes focusing on his rear to get forward motion..you want a slow trot or easy canter, a few times around and I attempted to stop him by looking him in the eye , stopping my movement behind him, and laying the rope down behind me, with a whoa... when they stop if they don't look at you and either turn away butt end out, send them around again with the rope, they are showing disrespect...
A few times around you may see your horse starting to lick or stick his tongue out and that's a submission.. "hey can i be your buddy now? I'll listen"
You want to drop the rope and ask him to whoa and look at you with some kissy noises. Once he looks at you see if he will come to you, if he hesitates pick the rope up and send him away again for a few rounds and ask him to whoa and look at you, let that be that until another time. You always want to end on a positive feel.
Keep working on that until he turns in and comes to you, you can kissy noise and turn your shoulder in to get him to come to you. Then you can work on him turning inside and sending him opposite direction around the ring, you making him change direction, really puts you in the leader position.
I also want to work with Mister to give to pressure. You can do that with anything, your finger, hand, bridle, halter reins...You do that by giving pressure until the opposite leg moves or the head moves then release, it's a reward and you will see your horse more responsive to touching.
That's as far as I've gotten with Mister, and now he trusts me enough not to balk when riding and to trust me in the bad deep dark woods.
There's definitely a lot of methods out there. I bought Gawani Pony Boy VCR Tapes "Horse follow closely" from Ebay and they are super informative and I like his manner. Another great source is
www.roundpenmagic.com
Good luck and let me know how you do if you can!