I think you probably know about the difference between "Wo?/Where?" (which place) and "Wohin?/Where (to)?" (which direction), right? Well, when using "Wohin?" you usually have the option of adding the "hin" as a prefix to the verb instead.
(a) Wohin gehst Du? (verb: gehen)
(b) Wo gehst Du hin? (verb: hingehen)
(a) and (b) are synonymous, doesn't matter which you use.
In my answer, I will be mentioning the place I'm off to, like "Zur Arbeit", so we drop the "hin" (but you could add it, if you wanted to).
The exact same thing would happen if I were driving:
(a) Wohin fährst Du? (verb: fahren)
(b) Wo fährst Du hin? (verb: hinfahren)
Or, if you saw me carrying something, you might ask:
(a) Wohin bringst Du das? (Where are you taking this (to)?) (verb: bringen)
(b) Wo bringst Du das hin? (verb: hinbringen)
And in "X macht eine Party. Gehst Du hin?"/"X is having a party. Are you going (to it/there)?" you also need the "hin", because no place is mentioned in the question. (Plus, "Gehst Du?" equals "Are you leaving?")
BTW, I would most strongly advise you not to start worrying about German prefixes at this point! Just try to learn the meaning of verbs as and when they come up in your lessons or songs or whatever, okay?