It's not. The guides published on emberjs.com apparently track the master branch on github, so are regularly out of sync with the version offered for download on the front page, and at the moment there's a third version bundled with the starter kit. This completely tripped me up when I tried to get off the ground a couple of weeks ago, because things that were described as working in the guides just didn't, and it wasn't clear what I'd got wrong.
EDIT 'cos noprocrast kicked in at the wrong moment: Add to this a release policy of stuffing new functionality in every minor release, and you've got documentation that, for someone completely new to it, who doesn't know what they don't know, feels like a minefield. The one thing you want as a beginner is documentation you can trust, and Ember just doesn't provide that yet.
To learn enough get off the ground, I ended up writing an "assume you know nothing" tutorial (https://github.com/regularfry/website/blob/master/source/gui...), which I've submitted back to emberjs.