Is the manual still with the sewing machine, it should tell you how to use it, never have seen one like this.

If the manual is still within reach it should have instructions on how to attach it. If not then go to google and type in Sears Kenmore and the model. Maybe someone else has a web to go.

I have a few gadgets that I don't know what are or how to use either. So, don't feel bad!! Did you find an owner's manual???

I agree that it is for button holes.
I have an old Kenmore and the manual as a pdf.
I'll try to see if it gives instructions. Can't recall if I have that particular gizmo, but I'll look. I never use this machine 'cause I like the Elna better. :)

Talk about memories! I saw those buttonhole attachments and I could smell them. Mine had a very distinctive plastic odor. It's been years since I thought about my old Kenmore. We had fun. Thanks for posting.