Oh goodness... it has been so long, I do not remember... BUT if memory serves, I followed the ARCH wiki to get Jack working properly... Good Luck!
I did some looking at the Arch wiki and it turns out that you will need to setup Jack to work with ALSA, not Pulse... As stated it has been a very long time since I used it... Dad's old guitar is not in playable shape so I will need to do something else if I want to setup a demonstration... anyway you should not have much trouble setting it up when you peruse the You are not allowed to view links.
Register or Login and the You are not allowed to view links.
Register or Login support page. The software you use may also have their own page for setting it up with Jack, I would imagine the procedure is similar.