Just remove the handles on each side of the headliner of back seat. Pop off the plastic trim with hands or plastic pry tool. Pull the headliner down and then tape off where you want to drill and use a step bit to avoid going too large or too deep. This entire process should take maybe half an hour. Then install the mount and run your cable to where you want and reinstall the trim. Crimp on your required connector and screw on your antenna.
Total job maybe an hour or so.