To attach the adapter to your Quad Lock mount simply install with a quarter turn motion just as you would with any Quad Lock device. The tab on the Quad Lock mount will lock into the adapter, securing it to the mount.
The design of the adapter is such that you can attach your Garmin in both the horizontal or vertical position, depending on your particular setup.
To attach your Garmin device to the adapter again install with a quarter turn motion just the same as any Garmin Edge mount.