Wiring a select button to jamma harness for MVS???

I have attempted to wire a select button to my jamma harness for my MVS board. It showed that it worked on the hardware test but it does'nt work when the board is in attract mode. The select button is for scrolling through the games on a multiple slot board correct? Because there is a select up and select down on the harness diagram for MVS. As far as I understand you just wire one wire to either the up or down select pins on the harness and the other wire to one of the grounds on the harness. Then take both wires and connect them to your switch. Any help please?

In the bios, set the option select when credited to OFF. In combo with freeplay, this will make the select button work.

Otherwise, insert a coin and see the select button work

Little confrused. So you go to test mode on the MVS board and then??? Do you go to Hard or Soft dip? I suppose hard because thats where you set coin-op or free-play. Please give more detail if possible. Thanks for the help though.

Go to Test Mode, then Setting up Soft DIP, then Setting up the Cabinet, then where you see GAME SELECT, switch it from WHEN CREDITED to FREE. Thats it.

Thankyou.