Make sure you are on the 'Shipments' page
Click the 'Add a new shipment' button, then then 'Bulk Add Shipments' heading at the top.
Enter the first BL and reference number as you would for a regular shipment.
Click the blue '+ Add Shipment' button for each additional shipment you would like to add.
When you're ready, click the green 'Create Shipments' button.
6. You'll be taken to a page you can refresh to see the status of each shipment. As they're created each shipment will show on your shipments page.