Where can I download a free User Manual?

In addition to the excellent guidance provided earlier by @Kurt Lang and @Grant Bennet-Alder, you can always find the Mac User Guide by clicking Finder > Help > Mac User Guide or by launching the Tips application.

Use the Mac User Guide - Apple Support

Since Mac OS software is a very large part of the user experience, you may find the MacOS user manual helpful as well. But this version is an Online reference manual, not really available as a download.

macOS Sonoma Manuals and Downloads - Apple Support

Mac Studio (2022) Manuals and Downloads - Apple Support

You're welcome. 🙂