Take a deep breath in, then exhale (breathe out) all the way until you can’t breathe out any more air.
Put the inhaler in your mouth and close your lips around the mouthpiece. (make sure the canister is pointing up). Your head should be tilted back just a little bit
Some people prefer not to put the inhaler in their mouth, but instead hold the inhaler about 1 inch (2 fingers wide) away from their mouth and keep their mouth wide open.