Cuabdo vamos a la biblioteca how might someone answer that

Assuming the question is "Cuándo vamos a la biblioteca", this is asking "When are we going to the the library?" So, the response would likely be something like one of these:
Vamos a biblioteca a las cuatro.
Vamos a biblioteca el miercoles.

Or, more simply, something like these:
Vamos en dos horas.
Vamos mañana.
Vamos el viernes.

1. incorrect, it's supposed to be me los das 2. correct3.incorrect, the "s" in las isn't supposed to be there because you want to know one answer not multiple