How to make Directory Opus 12 my default Windows file manager

This is a must for me, and it's not obvious to me how to do this operation.

Preferences > Launching Opus > Explorer Replacement

Where does it say, "Launching Opus" in Preferences? I don't see it?

You can also find things in Preferences by typing into the search field at the bottom left:

Ok, great! Thank you. So, I've done this, but DO still is not coming up as my default "File Explorer" replacing Windows File Explorer. What am I missing?

Sincerely,
Dave

In what context is Opus not coming up where you expect it to?

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If you mean File Open dialogs, see here at the top right of the page:

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