One of the Challenges that has been alluded to by several previous posters is that you have a plethora of options. You could learn how to configure FVWM, utilize the spartan email client and web browser that are all ready provided. Add a word processor and manually add a menu entry in the FVWM config file.
Another option is to install a Full blown Desktop realizing that it comes with some baggage in terms of bloat and security issues. The bare minimun of knowledge you would need is the package installation section in the
FAQ. There is a succint, online guide to installing
Gnome3 the steps of which are also replicated in the package readmes.
Similiar guides and Readme exist for XFCE4.
I put together a
guide to install a simple desktop that is somewhat OS/X like and intuitive to use. It takes more time but you actually see the configs and where they are installed. It even walks you through setting up user shutdown in sudo.