Stuck, found a bug, or want something the app doesn't do yet? Here's where to go.
Get the app. HeartBeat is in public beta. Install TestFlight from the App Store, then open the HeartBeat beta link on your iPhone or iPad. Beta builds expire after ninety days, so check TestFlight for updates now and then.
Start with the manual. It covers every screen, and the five-minute start gets you to a beat quickly if you're new.
Report a problem or ask for something. Open an issue on the HeartBeat issue tracker. Say what you were doing, what you expected and what happened instead, and if it's about hardware, which interface, controller or synth you had plugged in. A screenshot or a short video helps a lot.
If the app loses something. Every project is a folder in Files, under HeartBeat, with its samples inside. Everything autosaves a couple of seconds after you stop, and undo goes fifty steps deep, so the first thing to try is undo. The folder itself is yours to copy or back up at any time.
Plugins and hardware. Audio Unit plugins are other developers' software; if one misbehaves inside HeartBeat, it's worth trying it in another host too before reporting. For MIDI gear, the MIDI & Link chapter explains where notes go and how clock is sent.