Hello Yang,
The word adónde means "to where", and vas is the present tense tú form of the verb IR (to go). El fin de semana means the weekend.
So the question is: Where are you going this weekend?
When answering a question in Spanish, use the information given in the question itself, starting backwards:
El fin de semana, voy al cine. This weekend, I am going to the movies.
El fin de semana, voy a la fiesta. This weekend, I am going to the party.
With the verb IR, you need to use a right after to connect the verb to your destination. IR + a + destino (destination). If your destination is masculine (el cine, el parque, etc.), you need to combine a + el to get al. If your destination is feminine (la fiesta, la boda, la playa), then you can separate a from the article: a la.
I hope this helps! Feel free to message me if you would like a live sessionn.