When I started using Adobe Animate, I not only struggled with learning the program itself, but also with understanding different styles of animation. I was inexperienced and had no clue where to begin. Eventually, I began researching different styles of animation and practicing them on Adobe.
One of the first animation pieces I made was a simple one of a man walking. The walk cycle animation I made was much easier using image examples such as the one below.
As you can see, the short walk cycle animation movements are pretty similar to the image above. I suggest using these examples to help you get used to the natural leg movement when starting out. Here is a resource I found that could further help:
https://www.the-flying-animator.com/walk-cycle.html
Another thing that I found useful was this website with non-copyrighted art that can be used in animation:
This website gives you characters, landscapes, and backgrounds you can use as you practice. Here’s a good article about animation itself:
The Learning Repository 