APF is a great firewall system, and when coupled with BFD it's very much a winning combination.
I personally stopped using APF back in probably 2006 timeframe when CSF came on the market and made life so much easier (especially for cPanel/WHM users).
CSF & LFD by http://www.configservers.com
is all interface-able through the WHM system.
That being said, you're configuring a firewall for the system. If you're not sure on everything that it's asking, then you need to ask your system admin as they will know what each of the items are. CSF has a log of documentation (and in software documentation for configuration), but again, this is all about system security.