Gather 3 wooden planks
Gather 4 cobblestones
Gather 1 iron ingot
Gather 1 redstone dust
Open a crafting table
Place 3 wooden planks across the top row
Place 2 cobblestones in the left and middle of the middle row
Place 1 iron ingot in the center of the middle row
Place 2 cobblestones in the left and middle of the bottom row
Place 1 redstone dust in the center of the bottom row
Take the piston from the crafting result slot