In order to make a right-slanting cable, the cable needle needs to be held in the back of your work while you are knitting the next three stitches. Holding the needle in front while you work makes a cable that slants to the left.
Simply place the cable needle to the back of your work, being careful not to twist or drop the stitches. You don't need to hold onto the cable needle while you knit the other three stitches; it should stay in place pretty well on its own.
Once you have the cable needle in the right place, knit the remaining three knit stitches that are on the left-hand needle.
