Desktop Explanation

The first noticable difference for Windows users is the placement of the taskbar. The second major visual difference for is the three buttons instead of the one "Start" button. I believe that Mac users will have an easier understanding of Ubuntu because it has more similarities.

Top-Left Menu

The Applications menu holds a list of applications installed on your system. The menu can be edited by right-clicking the mouse button and selecting "Edit Menu." The applications are catagorized based on their relativity.

Many programs that were available in Windows or Mac are not available in Linux because of legal restrictions. All of the programs that are available are great replacements that were built by the Linux community. You can hover your mouse over a program button in the Applications menu and a tool tip will say what the program is used for.

The Places menu shows a list of common folders within your personal account and also shows a list of CD-ROM, flash drive, and other memory devices.

The System menu has options for preferences and settings. The desktop look can be adjusted in the preferences. The drivers, printers, and other system functions can be adjusted in the system menu.

Logging Out

Logging out and shutting down options have been moved to the top-right corner of the screen. The button is usually represented with a power button, but may also be represented with an "open doorway" picture. Click the button and a dialog will pop-up and ask for what function you would like to select:

Log Out
Switch User
Shut Down
Restart

Those are the basic options that are commonly used across OSs.