Although CDE encourages the use of the front panel for starting regularly
used applications, it is still possible to start CDE tools, or indeed the
OpenWindows deskset tools from a WorkSpace menu.
The Open Look Window Manager (olwm) uses $HOME/.openwin-menu

The equivalent of the .openwin-menu* files is $HOME/.dt/dtwmrc .

The syntax of this file is a superset of the .mwmrc file used by the 
Motif Window Manager (mwm). Note CDE will *NOT* look for a .mwmrc file, only
$HOME/.dt/dtwmrc

This file can bemodified to include lines of the form 

"File Manager..."       f.exec "$OPENWINHOME/bin/filemgr &"

to have a File Manager button on the Workspace Menu for example.
The easiest way to start is to copy /usr/dt/config/C/sys.dtwmrc 
to $HOME/.dt/dtwmrc and edit it.

dtwmrc can also be edited through :

CDE Application Manager->Desktop_Tools Folder->Edit Dtwmrc

The ApplicationManager can be located on the CDE Front Panel