Creating a "falling leaf"

Hi out there.
I am new to toon boom studio, but have managed to create a scene settup. ( With different layers) It is a forest shene. This time I would like to make a falling leaf, and animate it so it twists in the wind, and get smaller and smaller as it disapear in the background. Is there anyone out there that can tell me how I do this? ( I have used “instant motion”, but I can only make the leaf twist, and is not able to make it get smaller at the same time?
Best regards

Keyframes and manually scaling?