A Form is a screen in the web page.
In the above screen you can put, for instance, UIs, UDs and Niches inside the Frame.
When you put something in the Frame the GUI create a copy automatically of the UIs because the UI that you used create a Runtime UI in the fisical system memory. See more Runtime Data.
The GUI always show the UIs even if you put an UD or Niche in the Frame. See more Expanded UIs.
Now you can click and drag an item from the GUI to the end door, or create more doors. When you press F11 in a form, you can see the result that you will get in the web browser screen: You can click and drag the fields that you create to whatever position that you like or you can make Expert Flux do it for you automatically with the Automatically property.
You can add images as well like the ones you see in the photo.