Hi Jim,
A long read, but if you need "all" the basics, start here:
The 12volt Side of Life (Part 1)
But I'll give you some quick thoughts:
1. Your two 12V deep-cycle batts will be hooked-up in parallel and become your "house" battery bank. Negative goes to ground, of course; The positive post feeds all 12VDC circuits via fuses.
2. Your 2000 watt Inverter (which hopefully is an Inverter/Charger) has large red and black cables....and these go to the deep-cycle batts' positive and negative terminals respectively. Don't extend these cables if you think they are too short. Re-design your Inverter and Battery placements so you don't have to add extensions to these heavy cables.
3. Alternating Current (AC) input to the Inverter comes from the transfer switch on your rig. So shore-power or genset-power is fed to the Inverter's input AC terminals.
4. If the Inverter has two AC
outputs, one of these goes to to the circuits feeding TVs, AC receptacles, etc. Conventionally, if there is a 2nd AC output, it is a dedicated feed to the microwave. Be aware that the Inverter is not capable of powering your hot water heater or air conditioning units. And given the small battery bank you have, your inverter should not feed the refrigerator either.
5. And if the Inverter has a charger function, the heavy red/black cables will carry that charge to the house battery-bank. Now, to exploit some of that "charging" (so that the chassis battery is also maintained), investigate the Trik-L-Start device (find info in another thread on IRV2 or on the web).
6. Most gensets get their cranking power from the house battery bank.