Hey, I think the missing step here is to set up the virtual MIDI connections between the hardware and the software you’re running using aconnectgui or patchage. If you launch a patch via the button or the Pisound app, the scripts attempt to connect all the controllers together, but that happens only once, on starting the patch. We do have an automatic solution coming for this which will also take care of hot plugged MIDI controllers, it will get released soon, but you can try it out already by following the steps outlined in my reply here Script for launching PD patch with MIDI without aconnect - #3 by Giedrius and another reply a bit below.
Please create another topic regarding issues using the button to launch patches with a bit more details, as well as any other issues you hit. 