Hello,
just to help you in adding a new user:

  1. First create the new user as a simple patient(Fill in the administrative date)
  2. then go to the "system" menu -> Permissions -> Permissions for XY(XY is the name of the new user)
  3. attribute a profile according to his duties (Physician, nurse, or system admin) to the new user
  4. choose a default page ( "Medical record")
  5. then save
    => the system will give to the new user a user ID(a number) and a default password which will be changed by the new user at his first login.
    Hope This will help.

For the use of PostgreSQL as database, have you had a look at the db.cfg file in C:\projects\openclinic\tomcat8\conf \ if you installed the .exe file downloaded here.
I think it's in that file that you should change a lil bit.

Armel N.