At the Search Results page, choose the question you want to trend by clicking on the question link. This should bring up a Question Profile page.
At the Question Profile page, click the "Locate Questions" link on the right. This will bring up similar questions that use the same response scale.
Check the boxes to select those questions you would like to trend. Remember that the questions should be similarly worded.
Finally, click the Create Trend button. The Gallup Brain will then display the trended information.
At this point, you can create a chart based on the trend data or create a CSV file.
Note: The Create a Trend option is not available for releases.