You learn the formulae for all Master-level enchanted items contained in the formulae sets you have learned via Enchanting Training.
You learn 1 set of enchanting formulae (chosen from the Magic Item Lists page) that you didn’t already know, choosing one type of item (Heavy Weapons, Light Armor, Jewelry, Banners, etc.) and learning all of the formulae (including any that are Master-level) for that type of item.