Believe me, drilling that first hole
is scary.

But the process was really not a big deal. Get the template postioned as instructed and tape it down, run the sharpie around the hole, but leave the template on for redundancy.

Drill some corner holes and cut it out. I left a pretty good margin, probably more than required, but felt that a little extra filing and sanding was worthy the safety margin. Pretty anti-climatic by the time it was all over.