Here are some helpful videos that guides you to creating the best looking graphical interfaces for Biamp Touch Panels, iPads, and iPhones. The GUI can also be reached from compatible browsers. The Biamp Control app for iOS / iPadOS can be found on the App store.
This video shows the difference between the Master page and the other normal pages:
How to create custom buttons
This video shows how to add a custom slider
How to start your own custom library of graphical elements:
Exporting an image from a slider or a button, in order to do some external editing in e.g. Adobe Photoshop or other photo editing software is very easy, have a look.