To use this tool, first put in your items. Use the export to petpage tool from either DTI or Jellyneo to put your list on the left hand side.
To put in someone else's list, go to their list either on Jellyneo or on DTI, right click, and hit "View Source." Copy the source code and paste it over.
Please note that for Jellyneo lists on either side, you will need to mark if the list is a wishlist or a tradelist. (DTI does this automatically, so it doesn't matter!)