The general tab allows for the configuration of how each account name type will be generated.
SAM Account Name
Determines the SAM account name for the user without the domain prefix. The SAM account name may include Variables and also the <n> token which represents a number that should be inserted into the account name to ensure that it is unique. This is displayed as the "User Logon Name (pre-Windows 2000)" in Active Directory Users and Computers.
User Principal Name
Determines the User Principal Name (UPN) for the user. This is displayed as the "User Logon Name" in Active Directory Users and Computers. This may include the token <username> which will insert the SAM Account Name into the User Principal Name.
Determines the common name for the user account. This may include the token <username> which will insert the SAM account name into the common name. When using special characters in the common name the character must be encoded otherwise the "An invalid dn syntax has been specified" error may be reported. For more information see http://msdn.microsoft.com/en-us/library/aa366101(v=vs.85).aspx
Allows an administrator only visible description to be defined for this account naming template.
For more information about the different types of account name used in Active Directory see the Account Naming section.