Hook tying device

I have a hook tying device, similar to one I last used 30 years ago - the
only trouble is I have forgotten how to use it!
length is around 4" just a little thinker than a pencil. Has a set of jaws
in the end to hold the hook, fastened by a simple threaded wheel; and a
piece of thin metal that goes over and under the jaws. The whole thing made
of plastic.

I anyone can help with instructions, or point me to an information site, I
would be most obliged.
John