Instructions

• Find an ancient city, or locate one with '/locate structure minecraft:ancient_city'

• Go to the reinforced deepslate rectangle, clear out the sculk veins, and you guessed it, light it with flint and steel.

• Go through the portal you lit.

• Look for warden ore, and mine it with a netherite pickaxe.

• Mine three more with a silk touch netherite pickaxe.

• Craft some deactivated tools with warden scales you mine.

• Go back to the portal and mine the corners of it with a deactivated warden pickaxe.

• Summon the warden boss with a structure like the wither's, replace the soul soil with reinforced deepslate, and replace the wither skeleton heads with the warden ore you got from mining with silk touch.

• Defeat the warden boss to get the warden's heart.

• Activate your tools like this:

or this: