I don't know if it's bc of the language (java) or something else, but I've never been able to grok apache data projects. I theoretically know what they do, but there's no way I can understand the code, e.g. [1].
The code you see in the beginnig is actually code for configuring a "route" from a source of data to a destination. That was for me the key to understanding it. Once you do, you will find the rest of the documentation easier to follow. The earlier versions of Camel put the config in XML filed, but most prefer the DSL approach
[1] http://camel.apache.org/etl-example.html