Ok. I know somebody hear has the EASY answer for me....

1991 Toyota 4x4 pickup has 4 wires for tail lights
Brake
Left
Right
Marker

My new led tail lights have 3 wires
Ground
Marker
Turn / brake...

How the hell do I do this

 

You don`t !! Unless you want to use a trailer light converter then follow the instructions that come with that to wire things up.

Toyota has the turn signal separate most others have all 3 in one bulb

I just use 2 separate lights one for the turn signals the other for the tail and brake light

 

each side should have ground, tail, turn, brake.... a 5-wire system. as mentioned, you need a trailer converter if you are going to run 3 wires per side. do the tail lights come with a module or instructions?