Installing solar panels to house.

Hello, I am new to this and soon will be buying a house with my mother. My mother wants solar panels in the new place to save some money if it doesn’t have one already. I read the incentives, tax credits, and other stuff based on state. I am thinking of buying the property in PA or NJ.

How do I find a reliable company? I remember seeing videos of the company some people used went under and couldn’t get further support from them later on. Is there a way to make sure this doesn’t happen? Do I have to get the solar panels myself and then contact an installer, or do they do that themselves and know the amount needed based on the monthly electricity bill?

Since it seems I will be contacting multiple different companies, is there something I have to make sure to ask them to know I can trust them?

Sorry for the questions, but I only managed to see posts like this from last year. Just want to make sure I am spending my money wisely with a good, reliable company.