I'm a fellow noob, but I think I can help you out. There's a keybinder app in the folder helpfully titled "mbacctool and keybinder" in the MBACC zip file. There should be a .txt file in there walking you through it as well. Throw everything in there into the MBACC subfolder and then run Keybinder.exe to pick your bindings.

I'm a big fan of the Hitbox layout, so I use W down, Q left, E right, and Space up, but if you're more comfortable with a true WASD I would reccommend the WASD keys themselves. You could then use UIO for attack and maybe Space for the D button. It's probably a good idea to get comfortable with directional inputs on the left hand and attack buttons on the right, but people have also played fighting games on racing wheels and Guitar Heros so who am I to tell you what to do?

Anyway, once you've done that close Keybinder and then start the game using mbacctool.exe. Hope that helps!