First you’ll have to kill the wither, ender dragon and the warden with just an iron shovel (no armour, no effects, no golden apples, just a shovel). You will then unlock a secret achievement named ‘The Journey of a MadLad' Then you’ll have to find a village and trade it from the villagers for 64 emerald blocks…. Hope this helps
Me, casually making a portal to hell: Okay, just gotta remember that ghasts can’t break cobble, so I’ll be good. Better get some gold though, gonna need protection.