Recommend a movie editing program?

Does anyone have experience with a free (or cheap) movie/video editing software? I’m looking for something simple to put together a course. So basically the ability to add audio to a series of slides.

I used to use the free Windows MovieMaker 2012, but they’ve discontinued it. My husband’s Mac is too old for iMovies. And most things I look up are for editing actual video clips instead of stringing them together.

I’d love to know if anyone has any recommendations!