I need to build a GUI that has flight instruments in it. I found these ones , however I can't figure out how to use them with Qt Creator/Qt Designer. One way that was recommended online is to promote a widget to a new widget. So I dropped a widget onto a form and tried to promote it to WidgetNAV. However during compilation I got an error saying that WidgetNAV.h was not found. Clearly I'm missing something here, would anyone be able to help me out?