This company is manufacturing elevators I assume.   I do not know any place you can get to look at an example with similiar complex processes. But I can try to give som guidelines on how I would approach such a project.

How many workcenters are there in this production?  A work center deliver a product.  Either the finish elevator,  or a part of the elevator.   You need a list of work centers. I guess there is several work center thar make part of the elevator.

You have two basic principles: Multi level BOM and single level BOM

Mulitlevel: A work center deliver a part of the elevator, that is used in the next process step. That part is considered a semi finished product. It has it's own BOM and is a component in the next step in the production. You will have registered inventory of semifinished products, that is waiting to be consumed in the next operation.

The other option is called single level.  For producing a product it goes to several operations in different work centers and it is all set up in one BOM.  A BOM with all needed components, and the operations needed and components are assigned to which operation they are used. With single level you do not have registered stock between operations.

When to use single level and when to use multilevel? Most likely in a complex production you end up with a combination. An easy guideline is that if there exist physical stock on the shop floor (or in shelf or whatever) between work centers, you use multilevel. If the part that is produced goes directly into the next operation (like one by one), you can use single level. 

My first step in such a project would be to make a map of the manufacturing facility, showing work centers and the flow of materials into and between the work centers. 

Hope this helps you on the way.