editor

Hello, I am new to the editing files world. I downloaded (Android) an es file editor and I know its used to over lap parts, Which is my goal, but I just do not know how to do it. If any of you tech-savvy folks can lend a hand I would greatly appreciate it.

I'm interested in editing the textures slightly. nothing elaborate just a color change and maybe a logo or symbol. I've looked for .asset editors or is it as simple as a .png?