Click on a set that sounds interesting to you and look through the titles. You can click on a title to get more information about the book, including its Lexile level.
When you find one that you want to read, one that you believe you would enjoy reading, check the comments. If someone has already chosen that title, look for a different book that you would like.
You cannot chose the the same book as someone else- unless it has a number in front of the title. That number tells how many people can choose that title.
When you find a book that you are interested in and has not been chosen by anybody else, leave a comment with the title. Remember that you have to go through the whole "I'm not a robot" process to make it post. Then check back to see if it really posted! Sign your comment with your initials and period, just like you do on Mondays, so I know who you are but random internet people don't.