Exclusive use application

I am an owner in a block of 18 units. Our building has 3 foyers providing access to 6 units each. The foyer in my part of the building has a vacant room nestled underneath the stairwell. This room was crammed full of discarded furniture and building debris when I bought into the scheme around 6 years ago. After notifying the residents via the body corp, myself and another owner cleared the refuse from this room, it has laid vacant ever since. It has a door with no lock.

I wish to apply to the body corp for exclusive use of this area but am unsure of just how much information to put into my request. Can you advise?

Thanks 

Sarah