Two steps:
1. Tap Copy setup code.
2. Tap Share, then Add to Home Screen, and open PBR from your home screen. It will ask for the code - paste it.
Paste the setup code from the M5.
For a cash register on deals, alerts come through the Pushover app. 1. Install Pushover from the App Store and sign in. 2. Paste your user key (top of the Pushover app's Settings, or pushover.net). 3. On the M5, make the PBR app token at pushover.net/apps/build (name it PBR, Create Application) and paste the API Token/Key it shows.
Pick a sound and you will hear it straight away. Want your own? Upload an MP3 (under 500 KB, under 30 seconds) at pushover.net under Your Custom Sounds - it then appears in these lists.