I previously wrote on my blog that we taught children how to cycle in fifteen minutes. The bikybiky is unfortunately no longer available.
If your child has good coordination on a balance bike, can gain momentum and keep feet off the ground, he can normally cycle. Then he has sufficient basic skills for cycling. We taught children to cycle with a bikybiky in 10 minutes. An important rule is, hold the child and not the bicycle, saddle or handlebars. The best solution for the jacket is to put a tie around the chest under the shoulders of the child.
If the child does not understand the pedal movement, I lift the rear wheel, then your child can cycle in the air. Sometimes I take the pedals off, then the child can use the bicycle as a balance bike and get used to the bicycle. Parents consider this the egg of Columbus.