I decided the completely redo the wiring on the trailer that I bought because it was sloppy and not working properly...

anyway... here is what I have a wiring harness that is 4 pin with 4 wires running out of it.... labeled: Ground(white), Tail(Gray), Left Turn(white w/stripe), Right turn(Green)......

the lights that I have two wires running out of them one Brown and one Red.....

What do I hook to what??? and what wire do I ground from each light? I assume I will have to run a wire from the Tail(Gray) wire to both lights and hook to one of the wires and then run the turn signal wires to one of the wires and ground one of them.....

I am just wondering which wire goes to which one on the lights??? and which wire coming out of the light should also be grounded???

Also the harness that was hooked to the trailer was a 4 prong harness but had 5 wires coming out of it (2 green, 2 yellow, and a white). Do I need a harness like that instead of the one I have with 4 wires???? Please help me out I am struggling with this sorry if it was confusing.... feel free to ask me other questions... thanks.....

Give this a look.  It explains it pretty well.  I used this for my new utility trailer I purchased.  

http://www.accessconnect.com/trailer_wiring_diagram.htm

If you only have two wires coming out of your light then the light is self grounding.By that I mean the bolts that hold the light on is your ground point.make sure you clean all paint or rust from all holes.Also clean mount hole for white wire at the front of your trailer.One other tip don't use pinch on connectors.take the time to solder and heat shrink all connections,you'll be happy in the long run.