In OS 10.13.x, PrintMusic works with limitations but only if previously installed. Although it can read files created in other versions of Finale, you might run up against some of its limitations when editing those files.

Finale 25 can open anything (there may be issues with old or 3rd party fonts but, once you've gotten any resolved, you're good).

What you want to do isn't hard at all and having done it once, easy to repeat. So sit down, open the Help Files in your browser and get going.

You will have two choices on saving: Save will probably create a new file and pop a dialog box leaving your original file untouched—unless it's a .musx created in 2014; Save As will always create a new file. If extracting a lead sheet, I would open the old, Save As with the lead sheet name first and then I'd edit down.

I want a pony.

Seriously, Doug, you need to do some work with the new version. Most (all?) of your old songs should open in F25. Just resave them in the new format. If you haven’t used the program in some time, you might want to start just like a new user. Watch the videos, maybe work through the tutorials. If you run into a problem you can’t solve, come back and ask for help.

I would suggest you remove your email, for security.

I know I didn't give step by step directions but there are generally multiple ways to accomplish anything in Finale. Without a) seeing the original and b) knowing exactly what you want the finished project to look like ... We're happy to help with specific questions but no mind readers here, last I checked.