If we look at the example from the video, it will use the information in the csv and set the structure according to the setting in:
You can create your own objects and the objects can be dragged to new position according to your needs: http://help.ftrack.com/en/articles/1043966-managing-objects
If you want to change something on a current object, using csv, you need to reflect the structure.
So to add a description to already created task "compositing", in this example:
You could use a csv like this:
And get the result:
Hope this helps.