WH questions are used to get specific informtion, for example about a place, time or person.
did you go to the beach <-> when did you go to the beach
Does she love cake <-> what type of cake does she love?
wie - who: who did you meet at the pub?
wat - what: what did you do when you were in London?
wanneer- when: when does she go to school
waar - where: where did you stay?
waarom - why: why is he talking to her? - why isn't he talking to her?