ShuttlePRO and ShuttleXpress are simple shuttle-centric control devices by Contour Design, designed for user of digital audio workstations and non-linear video editors.
Plug the USB cable from the shuttle into a USB2 or USB3 port on your computer. The device will be automatically recognized by your operating system and will appear in any of the lists of possible MIDI ports in Ardour.
Normally, Ardour should be able to automatically detect a connected Contour Design Shuttle device and enable it. If it fails, connect the shuttle to Ardour, open the Preferences dialog, then click Control Surfaces. Tick the Enable checkbox opposite to "Contour Design" to activate Ardour's Contour Design shuttles support.
Once the device is activated, click Show Protocol Settings and in the newly opened window configure the device.
The configuration dialog allows setting up various settings for supported models of Contour Design shuttles:
Ardour ships with some sensible defaults for shuttle buttons.