Welcome welcome! Sorry I'm late giving instructions - I remember when you commented on the spreadsheet. Ok so I just created 2 .blend files for you:
- DOG-434E_model/MASTER_parts/WIP/ABM3010_dog-434e_interior_rear-control-columns_01.blend
- DOG-434E_model/MASTER_parts/ABM3010_dog-434e_interior_rear-control-columns_MASTER.blend
The first one is meant to be where you start your work-in-progress, saving iteratively as needed. After each modeling session, simply save over the mastered version to the MASTER_parts folder (second file listed above).
Feel free to link in other mastered parts for reference if you need. Also I placed the interior reference collage in the DOG-434E_model/REF folder. Let me know if anything isn't clear!