Coolleon101

Can someone help me? I want to add a custom mega evolution into the game but I don't know how to do it. I know it has something with changing the model of another pokemon and making the pokemon change into that except I don't know how to make the pokemon mega evolve into a different one. If you don't understand what I'm saying, here is an example: I want infernape to mega evolve but i don't know how to make infernape evolve into a different pokemon. I can only evolve it into itself. Please help

I have the same problem. I make the rom using the cmd file put it on my game and no changes. I have no idea why. I am using Pokemon Alpha Sapphire V1.2. Would I need a previous version or am I just doing something wrong?