Make a list of questions such as:
How many watts do you recommend?
What panels and controller do you recommend?
Is that PWM or MPPT?
Will there be a remote panel? Where would it go?
How adjustable is the controller for in-use vs. storage?
Where will the panels be located exactly.
Where will you locate the controller.
What method do you use to mount the panels to the roof.
What size wire will be used.
How will the wire get down to the controller and then to the battery.
Is this the best system or are you cutting corners to low bid and get the job?
What if I find I need 2x the power for my lifestyle?
And at least a dozen more.
Many of these questions you should already have an idea for what you expect.