This workout is very easy to learn. It is strictly a double poling ski that can vary from 30 minutes to 2 hours in length. There is no special timing required or extra equipment needed, just your classic gear. The best area to do this is on the parkway since most of the terrain can be double poled. There are also quite a few gradual uphills/flats that can be used to concentrate on technique. Double poling is a very important skill for racers because most classic races involve at least 50%-70% double poling (or 90% in the case of the Vasaloppet). It is probably the most underrated technique in skiing. Looking at someone double poling, it appears as if there is little too it, just plant your poles beside you and use the brute strength of your arms to push you forward. This is fine for people with arms like Arnold, but for a runner like me, I need some way to generate power to compete with muscle bound jocks.
The best way to maximize the power from your arms is to use your stomach as much as possible. The key is not to bend only at your waist but to crunch with your stomach so you use more muscles and generate more power. It is also important to be leaning forward and almost fall forward into your poling stroke. This puts your body weight into the poling motion so that it is not all arms.
The following articles give some insights into double poling technique and how to improve your double poling if you are interested: