System Workbench for STM32

Have you tried building a screen using the GUI builder? It puts together all of the code to put up a screen and route messages to your widgets.

I presume that you've already verified that you can read touch events and that the coordinates look reasonable. There's some interesting magic (read code I can't figure out) deep in the driver.

The STemWin demo is pretty involved since they're trying to demonstrate all of STemWin's capabilities. There is a HelloWorld example that is pretty straitght forrward. It doesn't use touch but IIRC it configures touch and it is pretty easy to add STemWin screens to it.