I discovered this little application a while ago called ‘namechanger’.  It allows you to automatically change the name of a large number of files in one go.  It has lots of options. You can add something to the start of filenames or to the end. You can do search and replace of filenames. You can remove characters, add in a date or add in a sequence of numbers. It’s very handy.  You can download it from here: https://mrrsoftware.com/namechanger/

This first screenshot shows you some of the things that you can do with name changer.

In this second screenshot I am adding the author’s name to the beginning of all these talks – all in one go. It shows you the old filenames on the left and the new filenames on the right.