Step 1: Tools and Materials
-exacto blade/box cutter
Step 2: Prep
Step 3: Measureing and cuting
Step 4: Sand
Next find the bigest drill bit you have, nothing to crazy, and drill the top hole slightly wider.
Then drill an even number of holes on the top for jets anywhere from 4-16 holes depending on your bit size.
I started out with four and ended up with eight.