Rules belong to Sources; each Source may have many Rules. You'll manage Rules that belong to one Source, and may enable and disable Rules as necessary.
Changes to rules are instantaneous, though you may experience a short delay with any long-running Rules that may not have finished executing prior to changing a Rule.
You may create an unlimited number of Rules for any Source (keep in mind that long running Rules may negatively affect web and other syncronous clients).
To create a new Rule:
You may update a Rule at any time. Keep in mind that changing a Rule will happen immediately, so the Event Debugger may be useful in ensuring your change is as you intended.
To update an existing Rule