You should have created the rule script in the Rules Composer.
For more information, see Creating and Editing a Rule Script
In the Rules Navigator view, select the project node.
The project opens in the Editor Window.
Under the Flow Rulesets section, select the flow ruleset.
Choose Open.
The flow ruleset overview page opens in the Editor Window.
Note
You can also open the flow ruleset from the Rules Navigator directly.
In the Rules Navigator view, expand the project node and select the flow ruleset.
The flow ruleset overview page opens in the Editor Window.
Under the Rule Scripts section, select the rule script.
Choose Open.
The rule script opens in the Editor Window.