I just guessed on where, both times it went well. For drilling I used a little oil, a small bit about 1/4in and then a large graduated bit. (not sure of the name.) It steps up in size the further you drill in, that will give you the perfect size hole.
Drill it SLOW!!! you should see shavings coming off, it will be very easy, but do it SLOW. You should be able to watch the bit turn around, use as much pressure as you can without breaking your bit. I used a hole punch to make a ding to mark the drilling point and give something for the drill bit to fall into.