It is important to know how to conjugate verbs in French, and does take some memorization. In case you need a refresher, here are the conjugations for the verb aller, which is used in this question:
Je vais
Tu vas
Il/elle/on a
Nous allons
Vous allez
Ils/elles vont
Since vous is the subject in this sentence, you need to use the vous form of aller, which is allez.
