There are no limits on the number of users you can create in your a3 system, and there are several different types of user roles giving a variety of permissions and options to the different personnel in your shipping agency.
To Create a New User you need to be a Manager or System Administrator user type.
Next go to Tasks on the Menu Bar and select 'Create New Person'.
On the next screen, input the New User's details, paying particular attention to selecting your Company Name, the User's Office, the Role (e.g. User, Manager or Accounting) and provide them with a User Login and Password.
Provide those details to the user, and remind them to change their password on login by accessing the user profile by clicking on their name in the top right.