Help in the "Clutch"

After Christmas, I go to see Minna at JoAnn's again.  She remembers me with my list of questions from Homer.  I've been trying to set up the serger for the chainstitch and coverstitch, but the book mentions moving the "clutch" and nowhere can I figure out where or what that is.   Minna has the answer right away. It's the slide at the bottom behind the cover, the "chain/cover select lever."  We talk about needles and optional feet.  I am beginning to realize that those who sew very well and produce beautiful creations are those who pay attention to needle sizes, thread types, and optional feet.   I ask about a pintuck foot for my regular sewing machine, and I'm aghast that it costs $41.95!  For a sewing machine foot!   I decide to buy the expanded instruction book for the Huskylock 936 for $32 instead.  This time.  I can easily spend another $800 on attachments and optional accessories for my 936.    I ask Minna about all the thread cones I inherited from my grandmother.  Can I still use them.  She says no, which is what I figured she'd say.  Don't know why I even asked.