Were to start? How should I do this? That was two of my questions, before I started this install. I searched the web, but info was limited. So to help my fellow club members & forum users. Here is my contribution.

 

I received this power inverter in December:
I have a friend that works with stainless steel, and he made me a custom bracket to mount the inverter to the back of my custom-made storage box, he made for me. I'll be mounting it behind the passenger seat.

By putting it behind the pass. seat, I knew I would need some heavy wire to handle the current of the 8 feet between the battery and the inverter. The inverter came with 10AWG wire 3 feet long with clips and eyelets on each end.
So to find out what gauge wire I needed, I headed down to the local auto stereo shop. I knew they would know. With them thousands of watts systems they install they should know. The kid that was behind the counter took a look at the inverter and the 10AWG wire, he said 8AWG would work. I believing bigger is better. Bought 6AWG battery cable.

 
BTW everything I needed for this install was bought at my local NAPA, Tractor Supply, and Home Depot.
As far as circuit protection is concerned I got a HMID fuse holder NAPA PN 782-1146:
I disconnected the battery and removed it. Also removed the passenger seat. Made working under the dash and mounting the inverter much easier. One thing I forgot to take a picture of was the holes I drilled through the firewall. I took my time doing this so I would not drill into anything of importance. I installed rubber grommets to protect the cables going through the firewall picked the grommets up at Tractor Supply:

Here is a picture of the wire going through the firewall:

After running the cable I attached the eyelets. Then mounted the fuse holder to the firewall, just below and behind the battery tray:

 
Then I hooked up the cables to the fuse holder:
I then put the cover on the fuse holder and used some RTV around the cable and grommets, to keep out any water that might get that high on water crossings:
Then I mounted the inverter:
I then reinstalled the battery and hooked up the cables:
And then there was power:
And here is what it looks like behind the seat: