Re: Good newbie guide to Fedora firewall
Disclaimer: I have no idea how much useful a firewall is but 'better safe than sorry' (not that I personally get sorry for anything...).
I am in a similar situation as you. I enter the router page and enable its built-in firewall.
Then I use system-config-firewall which is a layman's firewall GUI.
There's a page where we can block some services, I just block all.
Another page lets us allow some other things, I disallow every one of them (I don't even have a printer).
Everything works for me in terms of Internet.
So just use that, look at its tips and allow the least stuff you can.