the tonearm wires do not need to connect to the plinth.
it is best to connect the rca cable somewhere so the tonearm wires don't get pulled on.
you can simply connect the 5 colored wires coming out of the arm to a new rca cable.
red is right channel +....center wire of the rca cable.
green is right common – ....outside of the rca cable.
white is left +....same as + above,
blue is left – .....same as – above.
black to a single wire for the earth/ground connection.
connect the rca interconnect cable somewhere on the plinth to insure slack of the tonearm wires.
then you should be in bussiness!