How do you use a hopper with a furnace?

How do you use a hopper with a furnace?
Build instructions

Step 1: place down a chest on the ground.
Step 2: sneak (hold down ⇧ Shift ) and attach a hopper to the chest (side or top is fine).
Step 3: sneak and place the furnace on top of the hopper.
Step 4: sneak and place one hopper on the top and 1 hopper on the left side (important) of the furnace.

Build instructions
  1. Step 1: place down a chest on the ground.
  2. Step 2: sneak (hold down ⇧ Shift ) and attach a hopper to the chest (side or top is fine).
  3. Step 3: sneak and place the furnace on top of the hopper.
  4. Step 4: sneak and place one hopper on the top and 1 hopper on the left side (important) of the furnace.