This is a rule that defines how your number should behave at any given time.
ie During office hours and after office hours
Below, you can see an example of how to set an Inbound Route with an office hours rule of 08:00 - 17:00 Monday - Friday, and an After hours rule of any other time period besides what has been defined for office hours
During office hours, calls will be routed to the IVR menu called PrimaryInbound
After office hours, calls will be routed to the IVR Menu called Afterhours