Check out Will Prowse YouTube channel. He has tutorials from beginners to advanced systems.
Very easy to understand.
Here is a very well written piece on "How much solar do I need ..."
https://www.facebook.com/groups/sola...ibextid=Nif5oz
If I was doing mine again I would install unistrut rails on the roof then mount the panels on Renogy tilt mounts.
Installing unistrut rails will allow you to hit a rafter with every mounting screw.
With tilt mounting brackets you can lift the panels to clean under them and inspect the roof.
Also, if you have to change a panel or decide to upgrade them, it's easy to swap them out. You don't have to drill new holes in your roof.