You would benefit from accessing the BMW Technical Information System (TIS)...the 'free' site was shutdown by BMW Corporate as it was an illegal site.
You can pay to access the authorized BMW TIS site, look here
https://www.bmwtis.com/#/login
This is the database of all vehicles and contains detailed step by step repair instructions for virtually any possible repair - it's the reference BMW shop Technicians use.
Good luck/Bill