How do I use a metered-dose inhaler?

Inhaler. I would recommend to go to the manufacture's website and get a handout or watch a video if they have one to learn how to use the device. Sometimes devices have different ways of using them. Alternatively go to your pharmacist and they can go over how to use the device.
Asthma. Exhale completely, then breathe in at the same time you press the inhaler to deliver a dose of medication. Some additional length of tubing is also recommended to help this.