The default directory layout of GPMAW is:
Beneath this directory are four directories
\bin\ - The location of the executable file, help files, license file etc.
\system\ - Common files for the use of gpmaw, in particular mass files, modification files, the unimod file etc.
\user\ - This is where user defined files are saved, in particular
\documents\ - Here you can find a number of pdf files describing the functionality of GPMAW. In particular the full manual (gpmaw91.pdf) and the introductory manual (dummiesguide5.pdf).
for more information on the directory structure please see here.