The great thing about the Cintiq tablet is that it allows you to mimic traditional drawing or painting.
The tablet will recognize when the pen is close to the screen so only touch the pen to the tablet when you are ready to draw.
Tap the screen with the pen once to 'click' on anything.
The two buttons on the pen can be programmed to serve as particular functions. See Customizing Controls
The tablet has three touch-pad buttons on the top right of the screen.
You can also access the tablet properties from System Preferences:
Choose the device that you want to change the properties for at the top of the window under 'Device'.
Use the dropdown menus for each button to choose the function.
In most cases you will need to change the pen properties within certain programs themselves, like in Photoshop. If you want to make the changes affect how the program will respond, choose the program from the 'Application' list ('All Other' is selected by default so that users don't have to change the properties every use).
You can also change the eraser properties by clicking 'Eraser'.