Knowing how to use a fire extinguisher could save your ife in an emergency. The key to putting out a fire with an extinguisher is to use the P.A.S.S. strategy:
P Pull the pin,
A Aim the hose,
S Squeeze the lever, and
S Sweep the hose.
However, before you use a fire extinguisher to put out a fire, it's very important that you determine whether or not it's appropriate for you to be fighting the fire and whether or not you'll be able to put it out. If you don't think you can fight the fire or if you have any doubts, evacuate the building immediately and call the fire department.