How do I import a PDF into Music Stand? Video doesn’t go over it

How do I import a PDF song into Music Stand? I found a video that claimed to cover this question but it actually doesn’t show how to do that. There is no apparent simple way to do this. May I suggest a version update with an added button to
“Import PDF”?

Please review this article: https://www.worshiptools.com/en-us/docs/71-ms-attachments

Note that you must already have a file for this song in your library. If the song isn't already in your library, you can create one manually using the "Create New" option. See the "Create New" option in the upper right corner of the "Add Song" window in the first screenshot in this article: https://www.worshiptools.com/en-us/docs/128-ms-setlist