A few notes about join-up
Work in an enclosed area where there are no other people or horses.
Keep his pace brisk, trot/canter.
Make him move in both directions.
Talk to him with a firm voice.
Watch his eyes, ears mouth and even nostrils
Don't ever hit him. If he won't move away from a swinging rope, try a lunge whip aimed at his feet.
Don't assume he hasn't joined up just because he doesn't give you all the signals, every horse is different so is how they ask for join-up.
Don't let him turn and face you head on, this is a defiant act and must not be tolerated.
Don't expect him to do all the work, you need to push him away and that could involve chasing after him.
Once he has signaled you don't make eye contact again for the rest of the session, unless it fails.
Don't look back to see if he is coming to be with you, just listen for him.
You don't have to have a round pen, but the smaller the working area is, the easier it is to keep your horse focused on you.
If your horse doesnt move towards you after join-up take a few steps away from him to see how he responds.
If he still does not respond with follow-up approach him slowly and stroke him softly from his shoulder to his rump on both sides then turn and move away.
If there is still no follow-up it is best to retry the session because the join up wasn't fully sucessful.