Unit numbering:

The letter indicates the building.
In three-digit numbers the first digit indicates floor number
In four-digit numbers the first and second digits indicate floor number.
Because the resort is built over a dune in some buildings the "first floor" is not number 1.
    It is number 4 or number 2.
In three-digit numbers the third digit indicates the unit number, from left to right.
In four-digit numbers the third and fourth digits indicate the unit number.

For example unit C407 is located in building C, fourth floor (ground level), seventh unit.

Building Locations: