You can take a look at my drag and drop example that I posted earlier on this forum.
If you want to make it easer to drag and drop this little dots, I suggest to change them into html shapes, place them in a group that is somewhat little bigger. Make the dropzones also a few pixels bigger than the drag-notes.
Take a look at these changes in your document: Drag n Drop 2.hype.zip (310.7 KB)
I also changed the background-picture to a jpg file for better file sizes 