All you get is a connector on the roof, a connector on the side (for a small self contained, portable unit), the wiring to the batteries and (in some cases) a small auto breaker.
You need, the solar panels, mounting, solar controller, fuses/breakers and disconnects and decent batteries. Some of that depends on the size of the system you want.
Lots of info from members here and lots of pictures too.
Here's my 520watt setup. (Because I like to show pictures of it..lol)
Two 160w panels
Morningstar MPPT controller
Morningstar EMC1 Ethernet module connected to a wifi router
Some breakers and what-nots