One of the major differences in using a Live workflow is that your shipments are created in real time as you are adding products to your batch.
As your shipments get created, they appear in the Working Shipments section on the lower left hand side of InventoryLab.
By clicking on the 3 horizontal lines to the right of your shipment, you are able to edit the name of your shipment, and your Box Content Information (if you elected to provide this when you first created your batch).
To edit quantities of items/delete an item with Box Content OFF, you will need to first delete the item from your batch Seller Central, then remove it in InventoryLab. If your goal is to edit the quantity, you will re-add the item to your batch in InventoryLab with the correct quantity.