For a platform with functionality there are of course lots of things to read and learn. The courses here are a good start but there are also reference material listed below.
In the Tech pages there are lots of information. They consists of several sections. In the Docs section there are reference documentation about the platform and in the Guides section there are more solution based descriptions about how to solve certain tasks. Then there is a Stories section where you can read what others have done and also share your own stories. And finally there are the FAQ and Changelog sections that is exactly what they imply.