1. Configuration of XFce4
Xfce is somewhat similar to the commercial CDE ("reminiscent of" as they say). Its developers call it the "Cholesterol Free Desktop Environment", and it is certainly minimal compared to others. It may be XFce or Xfce depending on the date of the document you read.
At the bottom of a XFce4 managed session is a small taskbar (known as the "Panel"), and on the left side of this (yes, coincidentally just where the Start button is in Windows !) is an image of an animal (mouse ? dog ? rat ? - it's a mouse apparently) on a blue cross. Henceforth this will be known as "Start". If you click on Start a menu is displayed, and the configuration options can be reached from here.
Selecting Settings and clicking on Settings Manager will bring up a manager, within which you can select various control facilities. These allow control of the Desktop, Panel etc.
Right-clicking in the background will bring up the same menu that you get if you select Start.
To quit, select the Quit button on the Panel.
XFce is so lightweight that although it is a proper "desktop environment" (as opposed to a simple window manager) it does not by default use a session manager. If you want one you have to install it yourself, see Software installation under Unix and install a package called "xfce4-session". If you want it to restart the same set of basic tools whenever you log in then follow the following procedure after you've installed xfce4-session. Logout and then login again, open just the basics (e.g. xterm, clock, exmh, firefox if you want it) and logout again. It will ask you logout, reboot or shutdown and there will be a tick box for "Save session for future logins". Tick that box then logout. Login and the session should be restored. Logout again and untick the "Save session for future logins" so that you always get the same "basic" session at startup.
For more info see the Xfce homepage