How does choir work? Very confused and unsure.?

I signed up for choir and i'm not really sure how it works. For example, I heard that we sing in front of someone and they assign us to a group. And when we sing, what do we sing? Do we sing any song, or the music scale?How does choir work? Very confused and unsure.?They'll probably ask you to do a scale, then match pitches on a piano to determine your range. Depending on the group, they may ask you to prepare a song or read some music. You should be able to find out from your choir director.