if you are producing a multi-level BOM product, and your quantity status appears as 'no quantity' or 'partial quantity' for the parts (sub-assemblies) you are producing, and not purchasing from your suppliers, those items will appear under manufacturing > fulfillment.
In this list you will get all the products for which you need to generate work orders. You can either generate a single work order, or summarized work order which will be a single work order with all selected work orders in it.
Generate a single work order
Select the product from the list by checking the box in front of it.
Click on the bulk action > Work orders, and confirm it by clicking OK.
This will generate you a work order with all the input items and work operations you defined in the BOM based product.
Generate a summarized work order
Select the products from the list by checking the boxes in front of them.
Click on the bulk action > Summarized work order, and confirm it by clicking OK.
This will generate you a single work order that contains all the products you selected from the list, along with their input items and work operations.