Looks like a control unit and maybe some cables?
Yes, that's it: In the simplest version, a "charge controller" and wire of sufficient gauge (thick enough) to minimize voltage drop.
You might want to add a meter to see what it's doing, but it's not necessary.
Do these come with clear instructions\ schematics? Like, How to connect to the battery?
Mine didn't come with much in the way of instructions, but there's fundamentally not much to it. Connect the terminals on the solar panel to the input terminals on the charge controller. Connect the output terminals on the charge controller to the battery. Make sure you connect + to +, - to - .
Are 2 batteries necessary?
No, not necessary.
But two is better than one in general, and if you're really dependent on electrical power (like, because you're running a DC-only fridge) then a second battery is insurance against cloudy days when you won't make much solar power.
I am in Colorado.
I hear it's nice there.
I have a 2010 Grandby. I read somewhere, I think here on WTW, that FWC might have run some wires for solar but, where do I find these?
Look on the roof: There should be a weatherproof/rubber-covered plug up there. It leads to wires that run down inside your cabinets...but exactly where they lead probably depends on your model. You'll need to add a connector to the end of the solar panel wires, a connector of a type to mate with the connector on the roof. Stan@fourwheel can answer this question for you.
One more thing: There are different choices for "charge controllers". I got a "MPPT" (maximum power point tracking) type charge controller which optimizes the voltage to feed the battery just the voltage that it needs without wasting power.
This is all the knowledge I used to install mine, and it works.
Others can probably give more-refined answers...
