Punch a tree until a block of wood pops out.

Open your inventory.

Craft a workbench with four blocks of wooden planks.

Use planks and sticks to make a pickaxe.

Smelt an iron ingot

Construct a furnace out of eight cobblestone blocks.

Construct a better pickaxe.

Attack and destroy a monster.

Befriend 20 stray cats.

Acquire diamonds with your iron tools.