There are three main questions in Russian: Куда мы пойдём пить пиво? (which means “Where are we going to drink beer?”), Где ты был? (“Where have you been?”), Откуда ты знаешь? (“Where do you know it from?”). You should know the answers → and the correct grammar.
The Accusative answers the question куда?, use the Prepositional to answer где?, and the Genitive for откуда?.
If you need to mention a person in your answer, use the following cases: к кому? (= куда?) → Dative, у кого? (= где?) and от кого? (= откуда) → Genitive.
Куда?
Where to?
Accusative
Где?
Where?
Prepositional
Откуда?
Where from?
Genitive
К кому? — to whom?
У кого? — whose (place)
at?
От кого? — Whose
(place) from?
Remember some commonly-used words