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After you has selected a source, then the list of products that can be assigned will show. You will select the product you want to assign then fill in the Assign Qty (which cannot be greater than Qty to Assign). After you have selected all the products, you can click on Assign button.
Qty to Assign = Qty to Ship - Assigned Qty.
Assigned Qty: The total qty of the items have been assigned to all sources.
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After you assign products successfully, there will be a message. And then you will see the Assigned quantity of the product has increased to show how many product quantity in the order have been assigned to be fulfilled.
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