Most NMSs provide a way for the user to load MIBs. Loading a MIB is a way that an NMS can learn about new MIB objects, such as their names, object identifiers (OIDs), and the kind of data type.
Consult the documentation of the third-party NMS for information on MIB loading and compilation. This document includes instructions for HP OpenView and IBM NetView; but you should still consult the HP or IBM documentation, as those products may change.