Do you know what the pattern is? There are several ways to do mock cables and if I could look at the pattern it might help...but anyway I can sort of answer part of your question. When it says drop the stitches it just means to move them off of the left needle--you've already created a stitch on the right needle so you're not losing any stitches. You've just twisted them around each other.
"I will remember that no one has ever been killed or maimed by being adventurous with knitting, no matter how pointy the needles." The Yarn Harlot