Hello Frederick,
A good place to check out - http://docs.redhat.com
Since EVERYTHING Red Hat is there, it can be overwhelming. Look at Red Hat Enterprise Linux. If you really want to push yourself and go at an accelerated pace - I recommend looking at Red Hat Enterprise Virtualization (3.0 and later) - specifically the Evaluation. If you follow the Eval Guide and build a RHEV environment, you will learn a wide range of commands and procedures (installing software, registering to RHN, updating firewalls, etc...)
I found Michael Jang's book to be quite helpful when I switched from Unix to Red Hat Linux - RHCSA/RHCE Red Hat Linux Certification Study Guide

The Flash plugin is actually a really good example to learn with (in my opinion). It is an example of a package available from Red Hat as well as Adobe. And may cause a problem for you when you attempt to do updates.

Which is the first lesson: you have to be selective what non-Red Hat REPOs you add to your system. If you add a REPO to get packages that are not distributed by Red Hat, you risk the possibility of breaking dependencies for your Red Hat packages. (i.e. if you install X from external repo, you may not be able to update Y from Red Hat). There are a number of REPOs that work well with Red Hat REPOs - just do your research.

I have used the method that Stefan linked to: using the Red Hat Supplementary Channel version and found that the plugin did was not function as trouble-free as the one from Adobe (I don't recall specifics at the moment).

I put together a doc on my blog to cover my approach
http://unixrevolution.blogspot.com/2014/02/installing-flash-on-rhel.html
If someone can suggest updates or a better procedure, please let me know.