Click on 'Generate' under the top heading in the sidebar of the screen.
A window will appear where a branch can be selected and the range can be specified - these are the barcodes between which the carriers should be generated.
If 1 and 5 are specified, carriers with barcodes 1 to 5 will be created. These are fixed carriers, virtual carriers cannot be generated. Overlapping ranges cannot be specified - if a carrier with barcode 2 already exists, I cannot generate carriers 1 to 5, but I can generate carriers 3 to 5.
Click on 'Generate' to create the carriers - if successful, a message will appear stating that the carriers have been successfully created. Close the window and reload the page and the carriers will be visible in the table.