When should you use ‘Imperfetto’ tense and when ‘Passato Prossimo’ one?

‘Imperfetto’ is used to describe actions and situations in the past, to describe something you used to do in the past and for simultaneous actions in the past. On the other hand, ‘Passato Prossimo’ is used to describe a completed action in the past or to describe actions in sequence happened in the past.