The left button should back you out, and a left/right swipe should change screens.
Did you try a,restart ?
http://help.fitbit.com/articles/en_US/Help_article/How-do-I-restart-my-tracker/
Best AnswerYou might have the insert in there backwards, that's what was wrong with mine. When I took it out and flipped it around it worked. you can see on the sides where the one button on the insert lines up with the outside button on the band.