To do this without actually having web-server we are going to install a WAMP (Windows, Apache, MySQL, PHP) server plus WordPress software on our computers. This is not destructive! It does not change system files. The installation just set there until called upon by your web-browser. I’ve installed and uninstalled it tens of times with no problems to my computer. If you don’t have a laptop you may just watch but you must build a site to really get it.
After we install the software we will create a good site that you could build with WordPress.com then we will use a custom theme that will make it even better. Custom themes can only be used on WordPress.org sites.