Creating and setting up a new user
To create a new user the first thing you must do is log in to the admin site.
Once you are logged in you should go to the site section (click on the site tagb). If you do not see this section then you do not have the permission to create or edit a user account.

On the bottom right of this screen there is the create user form (1).
All of the fields are required on this form. They should be self explanatory, with the exception of the Administrators role. In general most of the users you create should be site administrators, so they can not access the site section and break anything. Super administrators have permission to go to any part of the CMS.
Fill out this form and click Create User.
You will now be forwarded to the update user page to fine tune your new user's permissions.

There are several things you can do on this page:
(1) Update their contact info and role
(2) Update their login credentials
(3) Set their permissions
(4) This is where you permanently delete a user
Focus on Permissions
Most of this page should be fairly self explanatory. One thing I would like to clear up is what the permissions are all about. You can individually fine tune the permissions for each of your admin users.
Section (3) is a list of each of the modules you have installed in your CMS. Just check each of the areas that you want the current user to be able to access and update.