Write the next sentence in the following story.

How to use a fire extinguisher
Instruct someone to call the fire department or call them yourself.
Evacuate everybody from the building first. Tell somebody to call the fire department or emergency services once that person is safely outside.
Even if you're able to extinguish the fire on your own, it's best to have the fire department on the way in case something happens. When the fire department arrives, they can check that the fire has been extinguished properly.