To take Attendance: 

• Click on the Interactions tab in your class page
  
• Click the blue More icon
  
• Click Attendance 
• You can mark them all as Present or Absent 
• By clicking the individual student's name, you can switch from Present, Absent or Tardy
• Once you are done, click Save

Note: When you choose to give an award to the whole class, only the students who are present will be given the award. But you can click on the absent student to give points to him/her explicitly.