There are two different ways to create a user depending on how your system is set up
If you have your Service Manager connected to Dimensions:
Click on System
Select User Defaults
In the Accounts Users pane, select the Dimensions user you wish to import into Service Manager
Under Service Manager Security Profiles, select the profile you wish them to have
Click Add
If your Service Manager is standalone:
Click on System
Select User Defaults
Choose Insert
Enter the following details
User Name
User ID
Password
Password Again
Choose a Security Profile
Press OK