Hello Joan
Have just been watching a DVD of a couple of players on their Technics organs, (Not sure of the models) and I noticed on both that there was a compartment by the side of the lower manual with a flap that either lifted up or slid back, and from memory I am pretty sure this is were the controls were for the disc drive, when fitted by the factory.
You may have to have a close look if the knob or handle is missing, as it is not immediately obvious. (Please bear in mind that it may be only certain models that have these controls, and that as your model did not come with a disc drive they may not be fitted, thus precluding the use of the disc drive)
Hope this helps

Bill