Be sure to apply a small piece of tape on the location you're going to drill, to prevent any flaking at the point of entry of the drill bit.
As for the warranty, if any damage results from the installation, regardless of who does it , except for someone they "your guitar manufacturer" approves. The damage will not be covered. Any other problems that may develop, not related to the strap button should still be covered.
Like "pix" said, be sure and not drill any deeper than you must. Also "imo" as for the drill bit I've always used one "at least" the size of the screw shank at it's largest point, so only the treads cut into the wood. This way the hole does NOT need to expand to accommodate the screw.
Also you might want a piece of material between the strap button and the guitar when finished, sort of a gasket if you will. In a hand rotary tool kit they're some buffing accessories about the size of a dime, some kind of fiber, they work great!
Choose wisely my fellow chordian, if it goes poorly,
There is no "UNDO" button,and it can be costly.