I installed KDE, and managed to log into it, but can't figure out how to use it.

1. It keeps resetting to full screen brightness and full sound volume. I have a light sensitivity and it hurts my eyes until I reset things to minimum screen brightness. [and on some machines, I have to put a sheet of paper in front to soak up the excess brightness].

2. It hides my files. I couldn't find an easy way to open a file browser, or anything I could add to the panel to open a file browser. I can't rely on search, both because of my injuries and because if my arms heal I'm planning to sort out some things between two computers [one old, one not-as-old] with three different operating systems.