You made the graphics by your own ? If yes np, you need an animation for attacking like an punch.
https://www.scirra.com/tutorials/253/how-to-make-a-platform-game
Make this animation and on collide play it ;)
For sure, it will need some more configurations(like stop following while hitting and so on) but this is the basic.
<font size="4"><font face="Times New Roman, Times, serif">And if i didn't make the graphics my own?</font></font>