Follow the instructions for connecting MIDI Designer as usual.

Follow these instructions for connecting generic MIDI to Ardour.

Step 2 states:

2. Connect Ardour’s MIDI port named “control” to whatever hardware or software you want (using a MIDI
patchbay app)

For this, we’ll use a Live Routing the MIDI Network Setup, mapping to “control”

Then follow the rest of the instructions from Ardour.

Note: You must start Ardour before you attempt to map the Live Routings to control (otherwise you won’t see them).