How to connect Lamm L2.1 Deluxe Pre-amp to Lamm 1.2 Reference monoblocks

Just purchased a Lamm 2.1 preamp Used. It did not come with a manual.   I want to validate the correct way to connect this with RCA connectors to my 1.2 monoblocks as the 2.1 Preamp does not have balanced connectors.    I have 2 shorting plugs with my Lamm 1.2. The 1.2 Manual is a little confusing but says these shorting plugs should go on the negative connections on each amp.  Thx