Once you've got the view marked up you simply call
ko.applyBindings(model);and Knockout takes it the rest of the way.
Let's walk through a simple example as that'll make things more clear (I'm going to use the same Login UI example as Derick Bailey used for his first Backbone.js post so it's a bit easier to compare apples-to-apples... hopefully).
The layout is very similar to a Backbone view except that in a Knockout view you add extra 'data-bind' attributes.
Notice the 'data-bind' attributes in the markup. These dictate how knockout will bind the model we provide to the UI. Let's move on to the model now.
Once we've instantiated a model object we simply call ko.applyBindings() and Knockout does the rest. (Note that the second parameter is the HTML element that should be the root of the binding. It is optional if you are only binding one object to your page, but I think in almost any application you'll get to a point where you want to bind multiple objects so this shows how to do that.)
At this point Knockout will keep the UI and model in sync as we manipulate it. This is full 2-way binding for the text elements. So if the user types in the username field, the model's username property is updated. If we update the model's username property the UI will be updated as well.
Derick noted in his blog post the mixing of jQuery and Backbone.js. I'm doing some of that here, but I think Knockout.js doesn't need jQuery as much because of how the binding is declared (on the HTML elements themselves).
I'm going to try to follow Derick's excellent series of posts on Backbone.js and comment on how the subjects he discusses compare and contrast with Knockout.js.