To be honest the easiest way is to first record your screens,
and correct all errors etc. Then record your voice whilst playing
through the content you have recorded. You can record audio slide
by slide or by playing th ehwole project through.
This minimises the need to restart recording your audio if
you make errors in the screen recording.
It is the simplest way. You can also delete individual audio
slides and re-record just the audio for that slide, which also
helps later on down the line should you add further slides to the
project, rather than having to edit one large audio file, you
simply insert the new slides and record the audio.
Webbo