"What do you do this weekend?"
Translation:Mit csinálsz most hétvégén?
I don't understand the rule for the correct order of the elements of the sentence. that is when the time complements goes at the beginning of the sentence and when it goes at the end; whether the objective come before of after the time,... I make lots of mistakes of this kind and still I don't fully understand the rule
You decide whether you are asking after the subject or the object of the verb.
Mi áll az asztalon? "What is standing on the table?"
Here, you are asking after the subject of áll "stand" - the thing which is standing. So you use the nominative case mi.
Mit csinálsz? "What are you doing?"
Here, you are asking after the object of csinál "do". You know the person who is doing (it's the person you're speaking to). But you don't know the object, the thing which is done, so you're asking after it. So you use the accusative case mit.
You can use other cases as well, depending on what you want to express:
Min ül a fiú? "What is the boy sitting on?"
Here you are asking about the something in the -n case (on what?) and so you use min. etc.