There should be a very large factory grommet in both sides of the front footwells that you can go though. Unless you have a sunroof in which case the drains are in those factory holes. Pic with blue circle is passenger side w/o sunroof.
On the vehicle I installed with a sunroof I ended up drilling to the right of the drivers side drain, just above the dead pedal. If you pull back the front drivers wheel liner there is a little access hatch you can open to visualize where the drain comes through, You will have to take off the trim panels up in the footwells to visualize the factory grommets.