On Thursday I went to the Harmony conference arranged by Oracle User Group Finland to speak about Galera clustering. (They chose the topic based on my suggestions.) The slides are now available on SlideShare. I'm pretty satisfied with this talk myself, the slides contain the most important steps you need to know to get started, but also the internal architecture of Galera, how it works, and what kind of replication topologies and load balancing you would want to use with it. And benchmarks of course.
The original LibreOffice OpenDocument format file is attached below.