Try to set the configuration with the menu and not the hot-key.
Open System Settings
You can either open it with the cogwheel symbol in the upper right corner -> System Settings...
Or you just open the menu and type "System Settings".
Open the Displays
configuration
In the "System Settings" menu, there is a monitor icon that reads Displays
, open that menu.
Change display settings
Your projector is like a second display. You should see a "buit-in display" for your notebook and a second display for your projector.
Click on it and switch it to "On".
You can then change settings if you want to have the two screens running, then it they will behave as if it was one big screen. That means you have to move the presentation window to the projector display. Or you can just mirror them and they will show the same stuff. You can also turn your internal display to "off" and just use the projector.
There is also some official documentation, but it doesn't say more than I just did.