Hi Youg2000,
Thank you for your message.
Do you mean what gets lost when deleting the Cubasis app?
If so, all of your personal data (projects, audio files etc.).
We strongly suggest to backup important files on a regular basis!
Here are some links to available Cubasis tutorials. Browsing the web you will find plenty clips from others too…
Getting started with Cubasis
Cubasis 3 Tutorials
Cubasis 2 Tutorials
Hope that helps!
Best,
Lars