How do I make the a custom character load the original players avatar?

As I am mildly terrible at scripting im wondering if anyone can help me with putting a custom char in my game with a custom gun on its right leg, which also has an animation in and it plays on a button. However I would like the horrible grey character to load the original characters avatar, if not, add a model onto the leg which when on keyDown would still play the animation but still have the players avatar. I'm guessing the script may have to start with:

local char = plr.CharacterAdded:wait()

-- And so on.

if not please correct me and if I could get help that would be nice.

Thank you,

oshawat00