Set up paint with a different paintbrush for each color.
Paint your pumpkin.
Allow your pumpkin to dry.
Put Halloween stickers on your pumpkin.
In the spirit of the Halloween season, we had to let our kids decorate some pumpkins for one of our Fun-Sized Fridays. It did not go well.
So this crackle pumpkin decorating kit was donated to us. We followed the directions
exactly as they were listed on the box, but crackle they did not. What we ended up with was a pumpkin that we painted silver and then painted black on top of and that's exactly what it looked like happened. It looked terrible. I looked it up and this pumpkin kit is like $10, it isn't cheap as far as pumpkin decorating goes. Someone had to have had good results for them to sell it, but we did not. It is definitely not kid friendly. (To be fair, I don't think it was intended for child use.)
So in the end, we just gave them Halloween stickers and let them cover their black pumpkins with the stickers. They looked terrible in the end, but the girls had a blast decorating, so I guess that was the bonus.
There are a plethora of pumpkin-decorating kits out there for you to use. If your kids are older, use stencils and let them carve. Otherwise, just get some acrylic paint, a shirt you don't mind the kids getting paint on, and let them go nuts. They'll have just as much fun, the pumpkin will be more colorful, and overall the project will be cheaper.
Grab your kids, grab a pumpkin, and explore life.