How to attach customer SI to support provider hardware SI?

Hello,

I will appreciate if you can help me to find materials or videos about how to I am, as Support Provider Partner, can add in my MOS my customers (clients) with their SI number.

For example I am, as a CUA of *** Jsc, who’s a SP (HW) want to see customers assets in my MOS to manage their SRs and understand which of their assets under our support.

I have their customer SI number and serial numbers but how to attach their SI to my MOS I couldn’t know yet.