You see where the red wire is going? Look there and you will see a black plug/grommet. Poke it out and you can easily get to it from the inside of the car up under the pedals.
Be sure to poke a hole in it and shove your wire through as to make sure it is water tight or buy another grommet, either way you want to make sure it is water tight. I currently have my JL audio power wire, turbo gauge tubing, escort laser shifter wiring, clifford alarm wiring, etc, so the hole is decent enough sized but be sure to keep ot as water tight as possible. If you got any more questions let me know, hope I could help.