It’s one of those jobs where you really want a drill press to make it as easy as possible, but you need one with a throat that’s at least half the width of the body, which means a large drill press. If not, then use a drill stand, or else a drill guide. It’s not a job you really want to try freehand as you don’t want the holes drilled at an angle.
I'll just add that if you do happen to have a drill press, but it's not large enough like Simon described, you can use still use it to make an accurate drill guide. There's a number of YT vids that show ways of making drill guides.
Making the world a better place; one guitar at a time...