Electrical systems can get complicated and very dangerous. If you haven’t purchased any batteries or components other than lights and fans, than a simple plug an play solution may be a good idea for you.
Look into something like a Goal Zero Yeti 400 portable power station. Then all you would need to do is wire your lights to a 12v 6mm 10amp port and the roof vent fan to the 12v car port.
A power pack like the Goal Zero Yeti can be charged and run off of shore power or solar as well.
If you still prefer to go the more complicated route then let me know the exact electrical specs of all the components you want to run (voltages and amps), and I can maybe help your further.