One of the decisions you will have to make is how to design your bill of materials particularly if you have multiple-production steps or sub-assemblies. The basic option are:
Include all sub-assemblies in the same bill of materials and use steps to delineate them or
Create assembly items for each sub-assembly or step
The decision comes down to the answer to this question. - Do I produce the entire assembly at the same time? Or do I inventory sub-assemblies/steps so I can build the top level product later? If the answer is No, then you should design your BOMs using options #1. #1 above is easier to implement as you would not be required to create work orders for each sub-assembly/step. For #2 you can create work orders for any sub-assemblies at any time then use them in the work order of the top assembly like any other component.
We have already seen a work order with multiple steps (see typical production work flow). The following Bill of Materials has 3 components, 2 off which are also bill of materials of which 1 has a component that is a bill of materials so that the structure has 3 levels. I printed the 'Indented BOM' from item editor.
When I add this item to a work order, you will see only three components. From the top assembly work order we can generate all the sub-assemblies by clicking Activities --> Drill Down.
If you add the column called 'Drill Down Ref' on the work order list, you can see all the work orders that derived from the top level work order.
All Order will also enable you to collapse all the components of the sub-assemblies onto a single work order. First though you must mark all the sub-assemblies as phantom BOMs.
Then from the work order, click Activities --> Flatten