Got my first app synced- any button press causes iOS app to crash.

I built a simple Russound remote and managed to get it synced up and displaying on my iPhone by following this tutorial:

Any time I press a button, the app crashes and the command is not sent to my Russound. Where can I look for logs or something to diagnose what went wrong? I’m sure there must be some info missing from that tutorial but I don’t know what it is. Thanks!