Any idea on how I could make the body take a step forward?

One leg out, other leg out. Best to start with just a two-frame walk cycle then progress.

Hey pal, be sure to keep all your work/questions in one topic to avoid cluttering the section.

Your question is pretty broad, you might want to narrow it down. Do you need to know how to make the frames? Do you need to know how to animate the thing?

We have a tutorial topic that you can go to to read some pretty cool tutorials on spriting/animating. I suggest you go take a look there.