I'm more about enjoying their development and having a safe run and coop for them. Chicks molt often, so trying to keep up with trimming flight feathers will be a struggle. They should have that safe coop and run! Mary
If you were to clip their wings what you do is cut the primary flight feathers on one wing. You only do one wing because the goal is to make them unbalanced when they attempt to fly, they don't like this and usually quit trying. If you do both wings you reduce their ability to generate lift, but leave them balanced, which isn't as effective.
The best way to learn to do it is to look up a video.
However you may not need to. What breed are they? If they are a large breed, like a Buff Orpington, once they fill out there will be much less flying.