Event Sourcing is supposed to be a great thing: silver bullet; at least. But only if your business case requires it. And if you event-source, you of course need CQRS. Unless you don't. After all, if it's business critical, you really want to use DDD.
Enough of the theory? How about some practical introduction to the world of commands, aggregates, events, projectors and process managers? After this session you'll surely have a better idea of what all of this is about.