Once you're done, you can end the session by tapping your card on the back of the device.
If you don't have your card, or the session was opened (started) by another member of staff, then you can close the session by clicking Forgotten Card and entering a super-secret code. If you don't know this code, then someone in your school office should.
Either way, once initiated, you'll be prompted for confirmation: Yes to end the session, No to go back to it.
If the application is online, all attendance is recorded in real-time, i.e. as soon as the student tap their card, they're recorded on our central system.
If the application is offline, then all attendance data is stored on the device and is uploaded to the central system once it's back online again. If you're recording offline, make sure that you get the device back to a university building, or to somewhere with better wireless signal so that this process can take place.