Oh, that's easy. Just use Save As, and give it a different name. Windows doesn't have anything equivalent to MVS' GDGs; you just type in whatever name you like. So if a document is named "Salisbury Market.xlsx", you could name the next version "Salisbury Market +1.xlsx", or "Salisbury Market (Tuesday).xlsx", or anything else that makes sense to you.

You know how to find "Save As"?