Just bought this towing wire to install on a nissan frontier.a unversal connector. I checked under rear of p/u truck ,saw wires going left and right and I do not know where to start.

I would like to install a universal connector to my pu truck .bought wiring. I need baby step on how to start

Most new vehicles already have a plug in installed for direct connection. Ask the dealer if and where it is and then buy the specific kit. Otherwise, you will have difficulty connecting wiring with separate turn and brake lights. I have seen people put in "universal" kits and have brake lights flash for a turn.