I’ve taught inner city children and this method would work as well for an adult. Lowering the seat so they can put both feet flat on the ground helps to reduce the anxiety of falling while learning to balance on a bike going down a gentle grass slope with no obstacles. Add using the rear brake instead of foot friction with the ground for stopping. Add putting one foot then putting both on pedals and continue the coasting down a gentle slope using brake to stop. Add pedaling with more braking and a longer slope

Add starting from a standstill on flat ground using pedals and using a solid pedal stroke that keeps the bike steady until the second foot finds its pedal. Keep working on getting a smooth steady start until it’s consistent. Add how to use both brakes to stop and more info about just using front brake problems and less brake power with just rear brake. Add info about body position and smooth pedal stroke info for straight riding. As confidence and skill grows gradually increase speed. Add info about steering and turning: slowing down before entering a corner, a little leaning and very little steering and inside pedal up. Add info about gear changing and use. Most importantly add safety lessons: riding the same direction as traffic, looking carefully both ways when crossing a road, stop at stop signs, keep hands on handlebar, lights and reflective clothes at night, wearing a helmet etc.

I would add a maintenance class to empower them in taking care of their own bikes!

Hope this helps…