Thanx for the info!
Although I saw a small protrusion on the top of the tonearm base, it's not an allen screw nor any other screw, and it's behind where the plastic dielectric stop is within the DIN connector. I tried to attach a photo of the cable and the cable inserted into the tonearm, but there is no icon which allows me to upload a file or photo. The photo shows that the cable connector hangs down a little, and it doesn't really take a lot for it to fall out.
I leave the ground spade on the tonearm side disconnected and just connect the ground spade on the phono preamp side. BTW, I've played some LPs already, and it sounds amazing.