or wherever the Samplitude program files are, called:
Tutorials_EN.pdf
You may also want to review this. I don't think there is a reference to it in the program under Help, and if you don't know it's there, you won't go looking for it. It can be quite useful (I should read it).
Thanks for confirming that the tutorials manual is with Pro X4, even it's for Pro X3. I think that Kraznet has covered most of the new Pro X4 features with his tutorials.
There is also a help guide for the eFX_Essentials plugins but I don't think that it comes with Pro X. Most of them are covered by the manual, but I think the eFX_Limiter was not included. Let me know if you want the document.