French article problem solving

There is a poster in the room. Do you know what is on the notice?

There is a cupboard in this room. You can put your personal clothes in this cupboard. "

It can be seen that dans le poste used the le definite article, because the previous sentence mentioned "il y a un poste dans la chambre", so this is the cabinet mentioned in the previous sentence.

But mettre des affaires refers to clothes in a general sense, without specifying which clothes they are.

hope this helps