I presume you're referring to the lapbelts of the harness set up?
If so, you will need to unbolt the seat from the floor and you can just use the OEM points used for the stock seat belt (1 on each side of the seat). Unbolt those points and attach your harness belts there. I don't remember which went on the outside, inside, etc, I'd have to look at my car but hopefully the instructions will point it out or you'll see the best fitment before you bolt it all back together.
The most tedious part about it all was unbolting the seat from the floor. Hope this helps.