This is an idea that's all over the web. Using the paint charts means you don't have to worry about matching / toning your colours. It's already been done. And it's free. What's not to love?
If you are going to make more than one of these, the easiest thing is to make a template.
I made mine using my Silhouette. You could also fold the paper & use a punch or scissors. Make the template the same size as the card base & use temporary adhesive to hold it in place while you stick down your punched shapes.
If I want to put a sentiment on the front, I just move the whole template up a bit.
