Set a pattern to indicate that the value constraint defines a string used as a regular expression that must be matched by the data in the associated type. The regular expression syntax supported is a subset of XML Schema regular expressions.
To set a pattern:
Select Add to the right of the Patterns field. This adds a pattern that has a default pattern (for example pattern1) and is in update mode.
Select Add to the right of the Patterns field. This adds a pattern that has a default pattern (for example pattern1) and is in update mode.
Press Enter on your keyboard.
Repeat the steps 1-3 for each pattern that you are adding.