Each time you touch an UI element the changed value will appear in the Learn Message panel.

This happens e.g. on slider movement, button pressing or value entering. The slider on the right of the panel will then be mapped temporary to the UI element. Depending on the type of the message you are able to assign a control range via a minimal and maximal value. Only this range will be mapped to a controller. You can “learn” a range by pressing learn range button and edit the UI element or the mapped slider.