There are plenty of tips to take away but here’s a couple below to give you an idea. GMBN say :
"The first thing to remember is that riding a bike should be fun and it’s the same with the kids. The bikes shouldn’t be a struggle to ride. They shouldn’t be heavy, too big or have adult sized components, or even heavy gearing on them. If they are, it could mean your kids aren’t going to enjoy riding as much as they otherwise would. This is what COMMENCAL kids bikes offer, with specific components on all models and sizes."
“Age doesn't determine the size of bike, height does, just like it does for the adults. Getting the right size is important of course, so that your child can ride confidently and comfortably. For this reason, COMMENCAL has designed their range with different sized wheels, so you can choose from 12'' bikes up to large models with 27.5'’ wheels for teenagers."
Find the full GMBN video here: