Step 1: String It Up!
Note: a zip tie or some dental floss looped through the loop will make it much easier to pull through.
Step 2: Lace It On
In the first, the cord goes up through the right eyelet on the pad, across and down out the left eyelet. Then it passes through the loop and forward to be tied off on the seat post. Repeat with a second piece of cord for the rear set of holes and eyelets. The advantage of this method is that it is pretty easy to swap the pad on or off. The downside is that you need two bits of cord.
The second way is to lace the cord through all four eyelets - this is a good choice if the pad is staying on the bike, since it minimizes cords running all over the place.
Hope this helps keep your pads on the bike!