You can choose to have your students sorted by their check-in status, or alphabetically. If you sort your students by check-in status, students who have been checked in will appear at the top, students with no status will appear under those students, and students that have been marked absent will appear at the very bottom with an X next to their name.
To edit the way students appear on the home screen and in each room, login to the app and click on the menu icon, and then Home. Click Manage on the right to change the way students are sorted for each room.
To mark a student absent, you will go to the Check-in screen, and then hold down on a child's photo. A pop up will appear where you can select to check the student in, or mark them absent.