Gain the trust of an Ocelot.

Find an underwater ruin.

Acquire 30 Emeralds by trading with villagers or mining.

Mine 1,728 Cobblestone and place it in a chest.

Use Shears to obtain wool from a sheep.

Wear a full suit of Iron armour.

Catch and cook a fish!

Harvest some leather.

Construct one type of each tool (one pickaxe, one spade, one axe and one hoe).

Construct a better pickaxe.

Construct a furnace out of eight cobblestone blocks.

Use planks and sticks to make a pickaxe.

Open your inventory.