Craft a Brewing Stand using 1 Blaze Rod and 3 Cobblestone
Craft Glass Bottles using 3 Glass
Fill the Glass Bottles with Water to make Water Bottles
Brew Nether Wart with Water Bottles to make Awkward Potions
Brew a Fermented Spider Eye with the Awkward Potions to make Potions of Poison
Brew a Glistering Melon Slice with the Potions of Poison to make Potions of Healing
Brew a Fermented Spider Eye with the Potions of Healing to make Potions of Harming
Add Gunpowder to make a Splash Potion of Harming
Add Dragon’s Breath to the Splash Potion of Harming to make a Lingering Potion of Harming
Add Redstone Dust to extend duration is not applicable to Instant Damage
Add Glowstone Dust to increase potency if desired
Use the potion on a target to deal instant damage