I would like to install an outdoor light on the outside of my garage between the two doors. I have a brick surface. I have a hammer drill and masonary bits. I want to tie it into the light switch that operates the lights in my garage. Thanks for any help in advance.

You could Drill through the mortar line and mount a pancake box on mortar to avoid harming Bricks, then to switchbox.
For permanent, I use a 4" Carbide Hole saw, drill in a little more than an inch and a half and an Octagon box fits perfectly.

Or you could drill a 3/4 hole and use a surface mount weather resistance box