Ok sorry just had to. Really you need to keep the plastic cool when you do it. Go slow and make sure you back it with wood or something. When I drill I use a cordless drill and water to keep it cool. If you don’t the plastic will melt and make a mess.
should probably use a small hole saw style drill bit..... you could use a large 3/4 inch standard bit, but I wouldn't recommend it. A hole saw bit cuts more slowly and methodically. Like bob82 said, need to keep it cool w/ water whilst drilling.