Simply look at the beginning of the file name. It should appear something like:
MPAF_[V Frame]_[Mod Type]_[Slot Number(s)]_[RestOfTheFileName].archive
If two mods designed to work with the M.P.A.F. framework are created for the
same V Frame (FV or MV), are the
same Mod Type (AUA, CAS, CMP, or OPR)
and take up the
same Slot Number (or overlap Slot Numbers),
they will not work together.
This file naming convention is somewhat new; please be patient while older M.P.A.F. mods are being updated to match the naming scheme, and if you are unsure what an older M.P.A.F. or Multi Pose Pack Framework mod would be considered, ask in this page's Forum tab, in the appropriate topic.
It should also be noted that OPR mods operate with a specific priority system amongst themselves. For more information on this, and clarifying examples, see the "Instructions - Mod Users" section of this page.