I have an error on one slide, can I replace just one slide?
At this point in time, that isn't possible for the presentation lesson type. Apologies as I know that's not ideal.
Our presentation builder is intended as a way to quickly throw together slides and audio. If you're planning to use a large number of slides, where you may need to update them from time-to-time, you may want to consider using a more robust/flexible option.
For example, you can use screen recording software to record your screen with the slides, and then add your audio over the top.
Check out this post for some ideas for adding presentation content to your courses.
And happy to help if you have any further questions at all.