Set layer transition timing
In 
Screens / Aux.⚓
Select a layer.
Set the global transition timing under the Take button.
In Properties, click Timing to show the corresponding settings.
The Opening and Closing graphs display the timings for all the layers in the selected Screen.
In Opening, enter a starting time and an ending time for the selected layer.
In Closing, enter a starting time and an ending time for the selected layer.
It is also possible to use drag and drop directly on the graphs.