GOG only supplies the manual for the vanilla game, but there was actually a reference card for Magic Carpet Plus/the expansion too.

http://replacementdocs.com/download.php?view.2175

It's not much but it tells you the storyline of events that happened after beating the original 50 levels, as well as some new features that the expansion introduces, including ability to save mid game.

Thank you!

Thanks! This will be my first time ever playing Magic Carpet (it never ran on my computers back in the days) so I guess I'll save reading this for after I finish the campaign.