That would certainly be a good starting point for you.
In addition, you don't have a lot of experience yet. Is it possible to get someone with a lot more experience to work with him for a while. Horses are herd animals and it is not natural for them to be away from the herd.
If your horse has never been used to working away on his own, he will be suffering anxiety at being on his own. If you can get him to where he is happy to go on his own and aim for a point a few feet further. Perhaps have another horse already standing beyond that point, say 50 feet so it's not too close but might give your fellow confidence to go that bit extra. Don't walk him all way to the other horse, just a few feet, then turn around and go back. Heap praise on him when he does well.
Gradually get the other horse further away - never ride out with the other horse, it is already in position when you ride away. Hope it makes sense what I am trying to say.
The other problem of standing still. Get someone to hold him whilst you get on and praise him when he stands still for you. You need to know that he knows that he needs to stand still whilst you are mounting. Make sure you are not poking him with your toe when you are mounting and keep your reins the right length as in not too loose.
After you have had someone holding him and he stands, use something as a mounting block so its easier for you and everytime he goes to make off you stop the mounting procedure and pull him up. Then start again. I always tell mine to 'stand' when I am about to mount so I verbalise what I expect from them - particularly the younger ones.
If you still have problems, definitely get an experienced person to help work through your dramas.
Only As Old As You Feel - Sometimes I Feel VERY Old