I installed an eautoworks harness a few weeks ago. My advice, pull your grill and headlights. Pop the hood and run the harness first. The end with the 2 hot wires goes by the battey. You will need to mount the relays near the battery since the plugs in the harness are on that end. I used the ground screw for the battery to mount the bracket. If you don't have cruise control you can mount the bracket in that area on the passenger side of the fuse box.
Run the rest of the harness down along with the factory wiring. Get a larger plastic wire loom if you need to for the section that will go across the lower grill area (mine barely fit in the stock loom). Zip tie as needed. Once you have run everything you will see that 3 male prong plug on the harness, that goes into the passenger headlight socket. Then your lamp will plug into the female 3 plug on the harness. On the drivers side you just need to plug the drivers lamp into the new harness, just pull the factory socket out of the way. Each socked on the harness has a ground you will need to mount. I ran mine up through the engine bay and mounted them using a radiator bolt on the core support. You can really mount them wherever you'd like, just make sure the area is nice clean metal (sand a bit if need be).
After your grounds are hooked up and lamps are plugged in and mounted, plug the 2 harness plugs up by the power end into the relays you mounted, doesn't matter which relay you use for each plug. Once this is done, pop your fuse box cover, and on the front end of the box there is another small plastic cap, remove that. There will be 2 power terminals there, this is where I mounted the power wires for the harness. Once you have done this try them out. Then put your grill back in and enjoy.