Apple Laptops Today Use one of Two Different Style Connectors on their Laptop. What is Pictured here is a DVI connector with the Apple-supplied VGA Adapter Cable.
Start by going to the Apple Menu and selecting System Preferences
Select the Display Control Panel.
The Display Preferences Panel is where you choose your Monitor's resolution, and to detect New Displays that Have been Connected to the Computer.
Select Show Displays In Menu Bar and Close Display Preferences.
You will have a new monitor Icon in your Menu bar.
You should be seeing your mac's desktop on the projector.