Thanks for the link Vikki, but I'm still confused as to what I need

"To convert from 2- to 3-speed requires only the materials to hook up the cable and the transmission properly. The conversion does not require a new detent, because the 2-speed and 3-speed are functionally the same (the 3-speed has an extra hard stop for second gear)."

Is a different cable needed? Everything is working right now, I just can't shift into first gear.

If the 3 speed as an extra hard stop for a second gear, doesn't that mean that I WOULD need a different detent??