Drilling to be "Reef Ready"

Hi all, I have a question I assume can be answered rather quickly. I recently picked up a 46 gallon bowfront w/ stand for free and after many hours of work resealing the tank and customizing the stand to my liking I found that i would have the best time drilling it to be "Reef Ready" so to speak. The bottom of the tank IS tempered so I can't drill that but the side panels are not tempered, at least according to the stickers left on by the manufacturer.
I personally don't have any experience drilling glass but my dad does and he would have no problem drilling it for me to help out, but I am curious about how we should drill it. By this I mean where the holes should be as well as size. Do I merely need a hole at the bottom of the back panel where I can attach an overflow in front of and then silicone an overflow in, or is it more involved?
This is my first time attempting to truly customize a tank as well as my first marine tank but I want to ensure everything is done as close to perfect as possible. :laugh: