Take your items to one of the self-service kiosks and follow the on-screen instructions.
It is important that you wait until the process is complete before removing items from the kiosk, i.e. all the items are issued to you and security de-activated (text turns green on completion) otherwise you may set off the security alarms.
If all the items are not read immediately move them around so the signal can be read.
You will be given a receipt showing the date all the items on your account are due for return. Items you borrowed today will be asterisked.