Having trouble with Teres Audio VTA adapter

I am trying to set up my Teres turntable again. I have not used the turntble for a few years and when I tried playing a record, it was obvious that things were out of adjustment. My Teres turntable is one of the older models; I purchased it in 2005, I believe it is a 165?? Anyway, it has gone through some upgrades, including replacing the lead-filled acrylic platter with one made of birch plywood, a different motor/battery set up, etc. I also added a Teres VTA adapter.

I am trying to set the VTA before checking the cartridge alignment. The rear of the tonearm, a Moerch DP-6 with a 12" arm tube, appears to be slanting down slightly so that it is slightly higher than the cartridge end. My understanding is that the tone arm should be basically parallel with a record set on the platter. I have twisted the knob on the VTA adapter from 0 (zero) and all the way up, but I can not see any change in the position of the tonearm no matter where the Adapter is set.

It has been years (3-4) since I have "played" with this turntable and I have forgotten the little I knew..... :-o No instructions came with the Adapter; after all, its operation should be pretty obvious and straightforward...
What am I doing wrong here? What obvious thing am I missing?

Holly