first, go to the item shop. at the top, there should be a button that says, "redeem". click that and here is where the codes will be typed in. (when typing in the codes, dont worry about capitalization.)

kiko is a little cat with splotches and this is the code for him: BEARDBOX. when done sucsessfully, it will give you a notification that you got a gift from @BeardBox. click on the present and it will give you the skin.

kato is a husky and looks a lot like max. this is the code for him. here's the code: JOSHANDKATO. when it is sucsessful, it will say you got a present from @JoshAndKato. click on the present, it will give you the skin.