The Security with Spring tutorials focus, as you'd expect, on Spring Security.
Get started with the Registration series if you're interested in building a registration flow, and understanding some of the frameworks basics.
Then, explore the topics you're most interested in, related to security.
Finally, have a look at some of the more advanced topics, such as the OAuth support.
Core Spring Security
OAuth2 with Spring Security
Spring Security with REST
Other Spring Tutorials
The entire tutorial in based on this github project. Watch and fork it at will - the project can be used as a starting point for a more full fledged implementation.