OK, this particular Behringer has, I believe, four pairs of outs. I think these are 1/4" balanced jacks. You need an adapter cable that has a single 1/8" stereo plug on one end and a pair of 1/4" mono plugs on the other end. Pick a bus and plug in the two 1/4 ends into the corresponding L/R pair. Plug the other end in the SB Live's 1/8" Line In jack. Route the signals that come into the mixer out to the bus you've connected to the SB.
You realize that with the SB Live you can only record two channels at once... depending on what you're trying to record, this can be very limiting. For example, if you're recording a band playing at once, you'll have to mix all the inputs down to two in order to record them at one time. So you can only isolate parts if you record them two at a time, with this card.