Hi,
I had a look at your keyboard user manual and it should be fully compatible with Hauptwerk.
Make sure to connect your keyboard to the computer before starting Hauptwerk. Also check, once Hauptwerk running, in General setting | Midi Ports that your keyboard is visible (you should have 2 columns with check boxes, one labeled Hauptwerk VST Link and a second one you will probably be your keyboard (if you only have VST Link, then Hauptwerk doesn't 'see' your keyboard. Read your user manual to see if you need to set some parameters to activate by directional communication).
If you Hauptwerk see your keyboard, make sure to *tick* the box for Console MIDI IN 1 and your keyboard. Then load St-Anne organ, right-click on the lower manual of St-Anne then press and release the lowest key on your keyboard and highest key, then click 'DONE' (see the Hautpwerk Installation and User Guide page 45 to learn more )
Hope that helps