Once the timings (including playing of video clips) are set, all you have to do is just play the presentation (if you want to stream with PowerPoint) or export as video (e.g. for uploading to video playing sites). If possible, I suggest playing the slideshow directly versus playing it as a movie whenever possible (due to the aforementioned bugs).
COVID-19 has brought out creativity in trying out solutions for teleconferencing, and we are seeing the pros and cons of the available solutions. Microsoft PowerPoint certainly has its uses for prerecorded presentations, but personally the bugs present can’t make me recommend it.