Place the brewing stand on the ground
Open the brewing stand interface
Put blaze powder in the left fuel slot
Put water bottles or potions in the bottom bottle slots
Put the required ingredient in the top ingredient slot
Wait for the brewing process to finish
Take the finished potions from the bottom slots
Add more ingredients to brew upgraded potions
Use nether wart to make awkward potions
Use glowstone dust, redstone, gunpowder, or other ingredients to modify potions