Only fill in what you want changed. Anything left empty or on Keep stays exactly as it is on your account. There are three codes, each with its own Generate Code button: Multiplayer Stats, Multiplayer Classes (Public and Custom Games together) and Zombies Stats. Copy each code you made and send it to your ticket in KiiLz Services.
The class name is the name on the class itself. The slot name is the name shown on the class slot in the menu. Both are set before the classes are built. Colour codes: ^1 red · ^2 green · ^3 yellow · ^4 blue · ^5 cyan · ^6 pink · ^7 white · ^8 orange · ^9 grey.
One code holds your Public classes and your Custom Games classes. In the tool you import each one on its own button.