Janey- I will try to pictures up, once I feel I am using it correctly
. What I have learned from looking at the book in the 2nd link, is that the side things are for different weights of fabric. They are labeled thin medium, and heavy. My youngest DS figured out how to put those things on the overcaster for me. It does work differently than the zigzagger (not "just like a regular attachment" as stated above) which I also learned from the Ebay pictures. I am so glad that seller put up so many pictures!
I had never seen one of these either, and since it was only $5 I grabbed it. It is in very good condition too, looks like new.