First, copy (not clone) a bunch of lstone_locker_1's into a room.

The "nth" property on each of these should be set to first, second, third, etc, as appropriate. (e.g lstone_locker_6::nth == first)

There should be a copy of lstone_machine_2 in the room. Should be a ranter that does trap every minute or so. It should sell lstone_key_4, and have "office" set on it to for example "New Southampton Left Luggage Office".

That's it!