Minecraft – How to make an armor stand in minecraft PE

Chainmail armor is not craftable in survival mode. You can only find it in loot chests in villages or as drop from Skeletons or Zombies who had it equipped. Also if you fish it up which is rare.

From the wiki :

Enchanting through an Enchantment Table requires a specific number of Experience Levels and Lapis Lazuli in order to be executed. Once the required tool/armor is placed, the player may select from a choice of 3 enchantments, each requiring different amount of levels and Lapis Lazuli. Once the player selects one, the item will be enchanted.

So, kill mobs and mine for XP, find Lapis Lazuli, and enchant you items.