XAMPP

I watched many XAMPP video on Treehouse and otherwise on Youtube. While i succeeded in installing and testing a website locally, the explanation is too technical and doesn't explain the logic of many steps. For example a more explanation of the xampp platform and buttons would help, a more explanation of the fields to be filled and why is a user wpuser or what it can be, and what is the site about field versus the database user field. A sort of illustrative map of relating Xampp functionality with what we are doing is important so we can configure future issues ourselves. More important, two key point by Zac about organizing sites- first do we continue to build all projects under HTDOCS, or under SITES folder created in the desktop, because the above 2 lessons confused me and contradict each other. Second i want to understand if i am building 4 sites or 5 sites as a practice at the same time, shall i list all of them in separate folders under htdoc? And FOR EACH I HAVE TO INSTALL A SEPARATE WORDPRESS?/? And what common xamp access to be used when accessing different site folders at the same time?