Samantha,
If you are posting through Auctiva, you don't need to "copy and paste" anything into your auctions. As long as you select the sellathon counter on our one-page lister, the Sellathon counter will be added and tracking stats will be collected.
All tracking info should be viewable online.
For more detailed answers and help, it's best to contact the Sellathon support staff directly. You can file a support case here:
http://www.sellathon.com/support.html
They also have forums here:
http://forum.sellathon.com/
-Kevin