of course "print it... grab a punch and a drill...." is describing a process that will give you better results if you take a bit of care and time doing it. Print out the page with the drill template from the build docs, make sure the print out exactly fits your enclosure, tape it in place, use a punch to mark all of the places where you will drill a new hole, and then drill a hole in those places. try not to drill a hole bigger than you need, and maybe start with a hole smaller than you need.
the goal is to get a good alignment for parts that will be directly attached to your PCB, and to make sure you have enough clearance for your in/out jacks and power jack between each other and the PCB.
and if your holes don't line up quite right with the parts, you can then start making your drill holes a bit bigger to reduce any tension on your parts and PCB from a forced fit.