Power Query MDX Index by category and date

Hi i'm new to MDX, can anyane help me?

I have a table with Order Id by cusutomers. I need to get an index column for each Order in a context of a client and date.

Pls don't suggest any DAX solutions - since the table has >32 mln of rows and any attempts to calcutale it in DAX led to memory shortage Error. The only hope left is that someone knows how to do it in Power Query Editor...