When starting out with backbone.js I also had a difficult time just using the documentation. Backbone is kind of the opposite of other popular MVC frameworks in that its un-opinionated, it doesn't enforce any strict organization which gives more flexibility but also makes it more difficult to learn.

What worked the best (however not optimal) for me was to combine the techniques used in the PeepCode(https://peepcode.com/products/backbone-js) screencasts and Thoughbot's book (https://workshops.thoughtbot.com/backbone-js-on-rails). Once you start getting in the groove of things the documentation is actually really good for quick look ups and you'll start to see that the framework is actually surprisingly tiny.

I also have a couple sample apps up on github that I used to learn backbone if you'd like to see some more examples: https://github.com/jwarzech/inspire_board https://github.com/jwarzech/realtime_hn