You define a new rule by its name (or number by default), of course by an if-type clause, ie, the conditions when the rule applies, and the action required when the condition is met. The description item #3is automatically generated by the e-mail client, here Outlook. You will soon realize that the number of combinations designed to discard unwanted mail is phenomenal.

For example, you can stop a large number of mail generated by traffic viruses by using such simple keywords as 'sex', 'girls', 'dollars', '$' etc.