This tutorial teaches you how to assign multiple materials to a skin properly.
This tutorial teaches you how to edit .sco and .scb model files (mostly used for particles).
This tutorial teaches you how to update skins which are in .wxy format.
This tutorial teaches how you can copy weights from your own skin (if you need to redo something) or from an original Riot skin (if you do not want to fully weight your skin yourself).
Here you will learn how to create your first remodeled custom skin. (This is the old version)