Craft or find an anvil
Place the anvil
Put the item you want to enchant in the first slot
Put the enchantment book in the second slot
Take the enchanted item from the result slot
Use an enchanted book on compatible gear only
Check that the item can receive that enchantment
Spend the required experience levels
Use a grindstone if you want to remove enchantments from an item
Combine enchanted books with other books or items using an anvil
Use a librarian villager to get more enchantment books
Find enchanted books in loot chests, fishing, or trading