Gather 4 iron blocks
Gather 1 carved pumpkin or 1 jack o’lantern
Place 1 iron block on the ground
Place 1 iron block on top of it
Place 1 iron block to the left of the top block
Place 1 iron block to the right of the top block
Place the carved pumpkin or jack o’lantern on top of the center block
Let the iron golem spawn