Faux Drag and Drop using Hidden Sliders

One of the key features missing from a UI perspective from PowerApps currently is the ability to drag/drop items on the screen.  It definitely limits some of your options in building interfaces and controls that work in a way users might expect.

However, there are notes elsewhere on how to mimic this behavior in some limited fashion using sliders.  This walks you through a common use case of having a Gallery where you can move items into various stages similar to a Kanban board in a manner that will seem intuitive to users.