I've heard the "best practices" for teaching someone (child or adult) how to ride a bike, and I imagine similar principles could apply for someone who is re-learning how to ride a bike. I don't know if you need to do all this, given that you once knew how to ride, but here it is if you like. I haven't had an opportunity to try this out on anyone yet myself. I heard it from someone who has taught many, many 9 year olds and a few adults how to ride a bike. He doesn't recommend training wheels at all.

Lower the seat fairly low, so you can sit on it with your feet flat on the ground. (This is the last time you want the seat like that. Once you have learned to ride a bike, if your feet touch the ground while you are sitting, your seat is too low, and it will cause your knees to hurt when you pedal.)

Take the pedals off if you can. (A pedal wrench is handy but I have done it with a regular crescent wrench.)

Sit on the bike and scooter it around, pushing or walking it with your feet. Only as fast as you are comfortable with. Get to where you can push off and keep your feet off the ground as you coast a little bit, maybe down a gentle little slope.

Once you can do that, put the pedals on, and try coasting one pedal stroke at a time, keeping your feet near the ground to catch yourself.

I've been told most people can learn to ride a bike with about an hour's worth of practice like this.