How are user accounts added?

You can use the Computer Management Console located in the Administrative tools folder. Go to "local users and groups" tree and select the "Users" folder. Right click in a blank area and select "New User". Here you can set the desired user name, password if any, and other information.

How are user accounts delected?

Again, you can use the Computer Management Console located in the Administrative tools folder. Go to "local users and groups" tree and select the "Users" folder. Right click in a blank area and select "Delete User" and then confirm deletion.

What use are groups?

Groups allow you to set permissions for a broad array of people. For example, if your adding a new user, and want them to have Administrative permissions, you'd just add them to the Group "Administrators". Whatever permissions you have set for the Administrators group would now apply to them.

What are user rights on folders and files?

User rights add or remove permissions for accessing folders and files. This is when you want only a certain groups or users to have a designated amount of access to information. If assigning access permissions to many people, it's suggested you use group permissions and add users to the groups instead.

What are the differant permissions and effects?

The permissions are shown below, for more information refer to the "Local Policies" section.