Our foster son suffers from asthma it was diagnosed when he was about 14 months, he had it before we got him but we were not in a position to act.
basically he's got two inhalers and a spacer a blue inhaler and a brown inhaler excuse the spellings but i think there called ventolin and salbutomol.
basically the brown inhaler is used once/twice a day and contains a steroid but don't panic about the use of steroids you normally hear about them in a bad context but with an asthmatic child your soon lean to love steroids, our son is not chronic asthmatic so doesnt require this brown inhaler daily only at the first sign of a cold or similar then daily until it clears.
the blue inhaler is used as and when required.
don't be alarmed over use of inhalers won't cause your child harm.
you'll propbably find any colds will become chesty and will normally be treated by an oral steroid such as prendisolone (spelling) the first few times you'll panic and get upset but you soon learn to spot the symptoms, it took us three stays in hospital but now we can spot the signs straight away before it gets that bad.
putting stickers on the spacer and letting the child shake the inhaler helps get them used to it, our sons now 2 3/4ish and can build the spacer up including the face mask and shake it ready for use.
the easiest way to start off using the inhaler is by lying the child on its back and you sitting with them between your thighs with your knees over the arms to stop them wriggling too much.
does your child like banana's? if so do these make the asthma worse? there one of the key trigger foods for asthamtics.
use google or another search engine and you will find loads of useful information.
hope this is of some benefit.