1. Connect the VGA cable to the adapter cable


VGA CABLE ADAPTER CABLE
2. Go to the Apple menu and select System Preferences
3. Click on Displays
4. Click Detect Displays
5. Choose your preference
6. Select the Arrangement tab and make sure Mirror Displays is selected

reference: http://www.kalvster.com/macintosh/connect-mac-smartboard.html
How to connect a PC to an output
1. Plug in the video cable to the data projector.
reference: http://www.elearning.soton.ac.uk/theme/smartboards/connection.htm