When a trackable order is dispatched to the courier a tracking reference is generated.
The tracking will not work, or it will show 'Advised' until the courier scans the parcel and it is processed onto their system.
Once this is complete the tracking will go live and you can follow the progress of your delivery.
Occasionally it can take a little longer for tracking to activate; especially if the parcel was collected at the weekend or just before a public holiday.