After purchasing a skin through the skin store, or for those who have purchased a premium version of Rust Console Edition and have received a skin pack, you can view these through the in-game Locker.
You can find the Locker through the Main Menu > Locker.
In the Locker you can find additional information about all of the skins which are available to you. To use these skins in-game, you will need to use a crafting table to apply them to the items you own skins for. They are temporary so you can change them at any time, you will just need to change the skin again from the crafting table.