The template is made to make 5 different size/ style envelope/ card covers.
Trace around the one you choose. Cut around the border. Score the flaps and fold and... viola!
The one I made here is the large- I did not choose to fold the top flap- I left it unscored and folded (can see the inside sweet paper showing).
The template comes with picture instructions to make it a bit easier to figure the templates out.