Here is how the Canada Post Manifest generation works in OrderCup:
Once you are done generating the shipping labels for your packages for the day, click on the Canada Post Manifests button on the Packages tab. This will load a overlay with packages that have not been transmitted to Canada Post for manifest generation via OrderCup. All the packages on this page are selected by default.
After the Transmit Shipments is completed you can print manifest for the currently transmitted shipments by clicking Print Manifest. This will generate a manifest and in response you will get back the printable PDF Manifest document that you will need to hand over to the Canada Post driver picking up the packages. Note that Print Manifest works only if you have done a Transmit Shipments
The Reprint (last manifest) link just allows you to re-print the printable PDF file of the last generated Manifest. You can use Canada Post Manifests --> Reprint (last manifest) in case you need to access the PDF Manifest document created by the last Print Manifest request.
Note: that manifest generation is a relatively slower process on the Canada Post side and the time taken increases proportionally with the increase in the number of shipments being transmitted. If you get an error response after you click generate saying: "9153 Error: The transmit process has not completed yet. Please try again later.", kindly click the Reprint (last manifest) link again after a couple of minutes and it would return the manifest for the shipments transmitted recently if the transmit was completed on the Canada Post side by then. If the transmit is still not complete on the Canada Post side you would get a previous manifest, so make sure you have the recent one or click Reprint (last manifest) again after a couple of minutes.