The "bottom" of the single cam bowstring (shorter end serving) will go over the TOP side of the bottom axle, and run clockwise around the tiny pulley, and onto Peg #2. PEG #1 will be on one side of the cam, and PEG #2 will be on the other side of the cam.
So, why did we ignore the cable slide at first? Cuz, by ignoring the cable slide, notice how the buss cable and the "bottom half" of the bowstring, naturally CROSS below the cable guard/rod? If the buss cable peg is on the LEFT side of the cam, if the bottom half of the bowstring attaches to a peg on the RIGHT side of the cam....pretty obvious that the buss cable will be CLOSER to your body, standing in front of the bow press, and pretty obvious that the bottom half of the bowstring, will be FARTHER away from your body.
That's why the cable slide is a wedge. One slot is a longer slot, more room away from the cable rod. The other slot is a SHORTER slot, less room away from the cable rod.
GREEN line is the buss cable. GREEN line, the buss cable is closer to the END of the cable rod.
So, the LONGER slot of the cable guide, runs closer to the end of the cable rod.