Hi,
You do not want to double click on the object in Step 3. All you need to do to map the source to destination, on the Green Items you would notice a '+' symbol, drag and put them on the drop item, you would able to map them easily that way, double clicking them would deselect the object.
For more clarification, what this video tutorial --
http://www.youtube.com/watch?v=ILtUftHxmag
Thanks,
Anjaneai