Temporarily load it as an Add-In?

The file is likely named Building Blocks.dotx.
That can be found in a profile folder:
c:\Users\{your username}\AppData\Roaming\Microsoft\Document Building Blocks\1033\16\

Once you find it, you could double-click on it to create a new document and run Mr. Wyatt's macro. It would create the list in the new document.

The above location is for English US language Word version 2016 and later.

To temporarily load it as an Add-In, instead, go to the Document Template button on the Developer Tab and use the Add button to add it to the Add-Ins list. It will stay loaded until the next time you start Word.