Step 1: Supplies Needed:
craft knife and cutting mat, optional but helpful
doo-dads to decorate the box
a PDF template, which you can find on my Scribd page
Step 2: Cutting the Felt
Trace the pattern onto the felt.
Using the scissors, cut the image from the felt; if you have one, use the craft knife to cut the little, rectangular slots (it's easier than using the scissors).
Depending upon the thickness of your felt, you might have to adjust the openings of the trapezoidal cuts.