The core of it all: building the app.
That's our primary activity at Humapps. We spend some of our time modifying H-DAM for clients who want particular apps. We spend some time on apps that we publish. And we spend a lot of time continuing to develop the included capabilities and functionality of H-DAM.
Apple (iOS) and Android together account for most of the market and we code for both of them. We recommend building an iPhone/iPad version first, because converting iOS code to Android code (the way we do it) is fairly easy, while there is no easy path from Android code to iOS.
If you market to Apple first, you can iron out any technical and marketing issues, then go to Android. This will reduce your risk and defer some of your costs into your income phase.
We can code for Windows Phone and other platforms, but strongly recommend you evaluate the economics of participating in minor platforms before committing.
Perhaps surprisingly, the task of designing and coding the app is often one of the smaller parts of an app based business: customer operations and marketing can be far bigger tasks. But the whole edifice rests critically on the performance of the app. It's easier to market something that is good.
H-DAM apps are good.