Hi Colleen, there is currently no built-in way to have curved motion paths in Edge Animate.
There is a classic workaround for this however, which involves horizontal motion on a child symbol, and vertical motion on the parent symbol. When played at the same time, these 2 motions combine to create a curved path (kind of like how the curved line on an x,y graph in algebra math class works).
nested child symbol: moves horizontally
parent symbol: moves vertically
Falling leaf example:
Falling leaf source: