How to connect your standard projector to your Mac using a VGA cable
1. Connect VGA cable to your VGA adapter (dongle) and connect the adapter (dongle) to your Mac.
2. You can connect this VGA cable directly to the projector, or to a jack on the wall if you have a mounted projector.
3. On your Mac, go to Apple > System Preferences In System preferences choose Displays
4. Click on the Arrangement Tab And check the Mirror Displays box.
That should do it! If you are not getting the Arrangement tab, that would indicate that something is wrong with your connection, either the dongle, or cable. See if you can borrow one from a co-worker and see if that one works. Submit a tech request if you need further assistance with the projector connection.