ROM Hack Help with importing custom portraits in FE Fates?

[StoneyEvan]

I'm not too sure if this is the place to post this but I've been having trouble trying to get my custom portraits of my male Corrin implemented in the game. I've been following deathchaos-25 guide and I've done everything right so far but when I have the completed arc file, I have no idea how to put it in the actual game on my 3ds.