Umm unclip it
If you don't know how a bra works, then you are not old enough to attempt to remove it from somebody.
They get slapped.
You call a girl with no bra on by her name. She is no different than a girl with a bra on, she is a person who made her own clothing choices.
Around the age 9-13, a girl will get her first bra or training bra.
There is no "normal" bra size. It varies from girl to girl.
A girl wears a bra by clipping using the clips.
Respectfully ask for permission before attempting to remove a girl's bra. Start by locating the clasp at the back of the bra and unhooking it carefully. Gently slide the straps off her shoulders and remove the bra.
You should not touch a girl's bra without her knowledge and permission. If you are not close enough to a girl to ask her how to touch her bra, then you don't need to worry about it.
No, that is just a form of foreplay!
Quite personally, I wouldn't. But who knows.. Some might, depending on how desperate..
If you want to take your bra off, then do it. If you don't want to take your bra off, then don't.
Just take it off like a padded bra or any other type of bra.