Doing LS Swap - I have no idea what I'm doing!

[EagleChief]

I took a look at my harness last night. It does have a grommet on the main harness to allow for entry through the firewall. Maybe there is enough wire there to mount inside the cab? I'm lost at electrical stuff. Luckily, the guy I dealt with labeled every connection and wire on the harness. The harness was made by PSI Conversion. Everything is already covered in wire loom and ready to go. I just have to figure out where to start as far as hooking things up and running the wires.