There should be six push-buttons on the front panel, the first button on the left should be marked "DISC". Around the back one of the DIN sockets is marked "DISC". The pin hook-up for the "DISC" input socket is as follows:
PIN 1 = RH channel in
PIN 2 = Common signal ground
PIN 3 = LH channel in
You should be able to use a moving magnet cartridge fed directly in to the "DISC" socket, with the RIAA correction taken care of on-board. If you want to use a low output moving coil you will need an external step-up device to match the "DISC" input requirements.
Hope this helps, regards and seasons greetings to all.
Richard