You want:
The Wiki is written for MODx 0.9.6 and you are using Revolution 2.0.
Note that Revolution is still in alpha although it’s fairly stable and getting close to beta. Most of the remaining issues have to do with usability and cosmetics. The core is quite stable and there are several live sites running Revo quite reliably.
The only issues for you would be:
1. Lack of documentation for Revolution. (I don’t think this is a serious problem once you have the tags correct -- it’s not THAT different and there are people here who can help you.)
2. Lack of snippets. Many snippets have yet to be ported to Revo. Work on this is ongoing as we speak, but if you need a working site soon that uses a lot of the MODx snippets, you might be better off with 0.9.3. I don’t think Ditto has been ported yet and that’s a crucial snippet for displaying data. I think the user management is also not fully developed in Revo yet (though I’m not sure about this) so if you will have a bunch of users with different security settings that could be an issue as well.