Get the basics of Ubuntu 12.04's Unity via a clear explanatory 27 minutes Youtube tutorial
Unity is an easy-to-use interface, yet, requires a basic set of informations, needed for an optimal usage.
After Ubuntu is installed and, especially for newcomers, Unity is exposed on the screen, due to its "intelligent" design, the users are to easily identify its components (launcher, panel, etc) and use them, nevertheless, there are various "hidden" actions that can make a difference (from an usability and productivity point-of-view) when using Unity, bits that are to be discovered and tuned (according to one's workflow) for a proper full desktop experience.
Ubuntu's Alan Pope has put together a handy Youtube clip, where, step-by-step, "vital" Unity components are explained across a clear pattern, such as launcher, Dash, Unity panel, etc, introducing the user to both components's identification and available actions, as related to the Ubuntu desktop as a whole.
Furthermore, the new users are carefully introduced to Unity's interaction behavior, exposing the methods of launching an application (via the launcher, via the launcher and/or the Dash, via the Unity panel, as in the case of System Settings), how to identify the focused and unfocused apps (in relation to apps' launcher "marks"), how to navigate through apps via the Alt+Tab Switcher, and, finally, the simplistic (yet complex at user's first look) usage of multiple workspaces.