This is a complex, technical question so some basic jargon MUST be used. It's not to talk over anyone's head, only the standard identification of critical features which a webmaster must be familiar with.
Learn Joomla? It's a canned CMS (Content Management System) which you control from a backend (Joomla's control panel). All that's required is that you can install it on a server (there are hosts like WebHostingBuzz which provide Specialist Hosting packages which are tailored to the higher loads Joomla - and other CMSs - require).
For your test server, though, you've unsuccessfully attempted to install a canned program for the "snapshot" of server tools (Apache, MySQL and PHP). I believe that the problem with the installation is that port 80 was in use by another application (I'm shocked that a printer would capture port 80 but Skype is known to do that, too).
While I "don't believe in" canned server sets like XAMPP, I fear that you'll be unable to install individual daemons even with the help of Kevin Yank's book (the FREE Chapter 1 which covers installation across many different systems).
UNinstall your XAMPP- you'll need to reinstall when port 80 is available.
Use services.msc to STOP any service which reports to be using port 80.
REinstall XAMPP. The things that you need to be aware of are that the server's name should be "localhost" (w/o quotes) and the IP Address should be 127.0.0.1 (by definition, the IP address for localhost, i.e., your computer).
XAMPP will have a directory where you MUST place the "website" you want to test. I'll not go into virtual hosts as that's a more advanced topic. Just install Joomla in the directory XAMPP specifies (normally htdocs or public_html or www or ...).
Since you're claiming to be a novice, may I recommend Kevin Yank's book: Build Your Own Database Driven Web Site. It was a good place to learn PHP and setting up a test server is where the book started - WELL WORTH THE TIME AND EFFORT and now in its fourth edition.