Where is the library?

This is a special question, where question, is a special interrogative word, indicating where, where,

Where is what, ask what, where is a certain place.

Library is a noun, which means library. Here, the definite article the is used in front of it, indicating that both the speaker and the questioner know the library.

The first floor represents the first floor. Use it to answer yes.

A complete answer library is at

First floor.

Because there is a library in the question, I also refer to the answer.

Library, so you can omit the library and use it.

It's on the first floor.

This means that the library is on the first floor. Please adopt