How to get into PIP mode

I have a used 1993  RCA/GE CTC177 tv set that says PIP on the front
case that I picked up junking.  The set works great once I fixed the
tuner solder problem. I only have a universal remote and am wondering
how to get into the PIP mode.  I know there is a service mode by
holding down the menu and the power and volume buttons, but don't want
to screw things up.  I tried finding the owners manual, but didn't
conme up with anything.

Suggestions....., TIA

Bob Hofmann