This page:
http://docs.telerik.com/teststudio/user-guide/verifications/data-bind-an-extraction-step.aspx

It documents how to create simple Extract steps, but what if you want to extract something else like the Title attribute of an element? This is an advanced topic that needs to be documented as well on this page.

It's explained in this video:
http://screencast.com/t/njlRbyPj