Basic question: How to use Morphing Layers

Hi, I tried to find how to properly use the morphing tool layers, but I don’t understand how I can draw or put a drawing in the morph layer… Toon Boom docs don’t clarify anything for me, thanks!

In the Thumbnail pane on the left side, click the slide that you want to apply a transition to, which should be the second slide you added the object, picture, or words you’d like to apply the morph effect to.
On the Transitions tab, select Morph.
official website