Make sure that the glass is not tempered glass or it will shatter. There should be a sticker on the bottom pane that will tell you if it is. You will need a glass bit. Do not use an ordinary hole saw!!. There is also a lubricant you can buy. However, I just use antifreeze. Make sure that you keep the area wet or the heat may cause the glass to break. The glass bit can be expensive, so you might be better off just going to a glass shop and having them do it. It is probably not worth it to buy the bit (even a cheap one) for one or two holes. It is such a simple task for most glass shops that they probably won't even charge you for it. I live in a small town, so people are friendly like that!!
