[jac1976]

I second timmy2 and also suggest checking out YouTube. I’ve found it to be a valuable resource when attacking projects. Beyond that, measure twice, cut once. I’ll add cut small as you can always extend your cuts. Cutting a small “x” for the aforementioned cutouts allows you to fold the material flaps over the edges of the backer to affix to the backside of the panel. The round cutouts seem to be done similarly, but with multiple reliefs at the edges to better follow the radius.