Each DLISTPAGEENT record in the DList represents a reference to an AMap PAGE in the PST file.
dwPageNum (20 bits): AMap page number. This is the zero-based index to the AMap page that corresponds to this entry. A dwPageNum of "n" corresponds to the nth AMap from the beginning of PST file.
dwFreeSlots (12 bits): Total number of free slots in the AMap. This value is the aggregate sum of all free 64-byte slots in the AMap. Note that the free slots can be of any random configuration, and are not guaranteed to be contiguous.