I ended up with a dual digit module of  a 7 segment display from Digikey
(part 67-1421-ND)
and it's got multiplexed pins.

Is there a general scheme for figuring out the data control lines on this or
otherwise how can I learn to use it?  I don't know the manufacturer off hand
to look up spec sheets so I was wondering if someone offhand knew how to use
multiplexed led displays.

Right now I don't know what any of the pins do.  Don't even know where the
common connection is.