100 + Amps off of a portable Generator?

First off, please excuse my ignorance to all things power. I'm a very technical person but power is my mind's kryptonite.

I am building out some production equipment in a car hauler trailer. It requires an AC unit on the roof that says it maxes out in worst conditions possible at 1800 watts. I also need some lights and (6) 20amp circuits.

I see that there are portable generators that go up to about 15,000 watts but I'm not understanding a few things...
1) how do I connect a breaker box to the generator?
2) these generators look to have 50a connections or 30a connections? How on earth do I get to 120 or 130amps like that???

For reference, I'm looking at generators like this: http://www.generac.com/all-products/generators/portable-generators/gp-series/gp15000e?lang=en-US

Thank you!!!
Steve