Applique is really not that difficult if you do it with one of the many iron on products out there. Find a picture. Size it. Trace it. Cut out the pieces and then use a very tight zig zag stitch around it all.
I think I would keep this very simple. Get the shield blown up really big and use it as a center panel. You could add borders that were either pieced or plain being sure to end up with the triforce in all four corners.
This is totally possible even if you have never done applique.