Your first stop should be the Official Tutorial.
Then I would suggest looking at the Samples. The samples do a better job than the reference guide in showing how things should work.
After that, I’ve written an overview and set of examples for working with some of the concepts. One that is very useful to understand, and not always obvious, is setting filters and parameters prior to load. The code for most of these examples exists on GitHub as various files.
Getting the values of all marks in a sheet
Embedding Multiple Tableau Views in a Single Page