Quando corresponds to the English conjunction when. When / quando establishes a temporal relationship between one action and another.
When he comes I ask him. Quando viene, gli chiedo.
We don't doubt in this case that he comes, even if we don' t know the exact time of this arrival.
The basic use is therefore quite simple. Nevertheless sometimes there are alternatives more suited in a certain context. An alternative to when / quando for instance is everytime / ogni volta if an event / action happens regularly.
If two action / events are happening at the same time better suited is while / mentre.
quando / mentre
when / everytime => quando / ogni volta
Quando / Ogni volta qualcuno fa una domanda, si arrabbia.
When / everytime someone makes a question he became angry.
description of two parallel actions => mentre
Quando / Mentre tu parli, io ti ascolto.
When / While you are speaking, I am listening to you.
In English as well as in Italian when / quando can be used as well as an interrogative adverb.
interrogative adverb when / quando
Quando viene ?
When does he come?
conjunction when / quando
Quando ascolto musica, sono felice.
When I hear music I am happy.
When / quando are temporal conjunctions, they collocate two actions / events on the time line.
1) One action / event can happen at the same time as the other.
When he speaks, everybody falls asleep.
2) One action / event happened before another action / event.
When he had said what he wanted to say, he left the room.
3) One action / event can happen after another event action in the future.
When he has done his homework he can do what he want.
We are going to see in the next chapter, that there are big differences between Italian and other romance languages like Spanish and French in how to collocate the action / events on the time line.
The first case is simple.
Quando describing two actions / events happening at the same time
Quando non è qui, nessuno lavora.
Everytime he is not there, nobody works.
Quando avevo voglia di stare da sola andavo al mare.