Quick rundown for anyone who doesn't know, MaGMML3 (Make a Good Mega Man Level Contest 3) is a Mega Man fangame that came out a month ago. It's a compilation of 176 level submissions that are ranked by judges and placed into a hub world with lots of extra content and challenges, and you can use costumes to play as other characters.
So yeah if you want to play as Pink just put this in your costumes folder in the game files