Each capsule pod comes with a small locker, either below your pod, inside or outside the room. The locker is operated using a 4-digit PIN:
The first time you use it, the digital locker should be in unlock mode:
To lock it, close the door, key in any 4 digits on the digital lock, then press #. The digital locker should now be locked.
The next time you need to unlock the digital locker:
Key in the same 4 digits on the digital lock, then press #. The digital lock should now be unlocked.
The locker is not big but would be just nice for a small to medium size backpack. The average size of a typical locker is about 30cm x 50 cm x 70cm (height x width x depth). If your bag does not fit, you need to leave your extra luggage outside the room, or inside your pod. Hence you may consider keeping only the valuable items in the locker.