I don't have the exact setup on a sun machine, but I imagine the concept is the same as in a windows environment.
There you'd run the "dmadmin" command. (in my case it's located in "c:\siemens\nxi6\bin\" i.e. Ideas 14 for those who speak I-deas...
Run the command, then select "memb" for member. In the next menu select "CR" for create new member.
The exact details depends on your setup.
You will probably want to look around before using the CR-command. E.g. the LT-command lets you see how the other users are set-up.
As I understand it's common that normal users are set as "manager".
Also you will probably need to be an administrator to create users.
/Mike