In most cases prepared for solar simply means they ran the wires from the roof to a location somewhere within the coach or in a storage compartment for a controller. Most coaches that i have seen sold in that manner had a tag in the general area of where the solar controller wiring was located.
As to adding solar you need to get the panel(s) and controller and once the panel(s) are mounted on the roof it should pretty much be plug and play.
US Army (Ret)
2020 Entegra Accolade 37TS
2019 Jeep Grand Cherokee Trailhawk (Toad)
FMCA - F432054