A good introduction to get started is:
Marble's Secrets Part I: Behind the Scenes of Marble...
https://blogs.kde.org/2008/02/09/marbles-secrets-part-i-behind-scenes-marble
Marble's Secrets Part II - Walking In The Shoes Of Slartibartfast ...
https://blogs.kde.org/2008/02/10/marbles-secrets-part-ii-walking-shoes-slartibartfast
Marble's Secrets Part III: The Earth in a Download
https://blogs.kde.org/2008/02/12/marbles-secrets-part-iii-earth-download
Marble's Secrets Part IV: Run Marble, Run!
https://blogs.kde.org/2008/11/20/marbles-secrets-iv-run-marble-run
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