Sumo The Five amplifier setup question

Hi everyone. I just bought a Sumo The Five amplifier that does not come with a manual. After receiving it, I realized that there are 2 RCA inputs for each channel. They are labeled with a + and - signs. I don't quite know which of the RCA input to use. Does any one have an idea ? Thanks.
Congrats on winning the auction; I had my eye on this piece as well, but had an unfortunate communication with the seller that caused me to not bid. I believe that it is simply an unorthodox way to implement balanced drive between amp and preamp. The preamp, which I take it you did not win, had similar outputs. I am not sure, but I believe that the only way to run this from an unbalanced preamp is to put balanced to single ended adaptors into the standard balanced inputs. These are made by Cardas, Rowland and others, and should also be available from most pro audio houses in a less than audiophile grade. Would you be so kind as to either post or e-mail me directly with your perceptions on the sound of the unit when you get it up and running?
That seems very goofy .... running each phase of a balanced signal through its own single-ended RCA cable. Is this truly what is being done? ... or does the amp simply have labels for + and - inputs to support inverting and non-inverting preamp outputs. CJ preamps traditionally have been inverting output while the vast majority of other product lines have been non-inverting. Support for each sounds nice as long as there is no sonic degradation in the process.
I will send you an email later regarding the sound of this amp. I think John is right regarding the amp's RCA inputs, these + and - inputs are for non-inverting and inverting, respectively. I plugged my pre-out to the + (non-inverting) and it works great. The inverting inputs also works, though the gain is much lower. I had to crank up the volume knob a bit to get the same volume.

Thanks for the inputs.
The - jack are where you put the shorting plugs. The + jack connect the rca cable

Shorting plugs are RCA jack with the +and - soded together

Your the + and - neg twisted together