After 5-7 days, the wine should be done with the heavy duty fermentation. You can tell by taking a hydrometer reading, or by just seeing a slow-down in fermentation activity. I decided it was time when my must was less frothy. A hydrometer reading confirmed that the must was more alcohol than sugar or water, with a reading of 0.996.
Remove the pulp and skins. Since I used a nylon bag, this is easy-- just lift out the bag, and squeeze out the liquid until all that is left is a dry pulp.
All of your tools and containers should be sterilized. I have a product called "EZ clean" from the brew store, but you could also use a campden tablet crushed in 1 gallon of water.
Rack the must into your carboy(s). In this case, I am using a 3 gallon carboy. For other batches, I've used 1 gallon glass jugs.
Add water or sugar water to get the volume up to 1-2 inches of space in the neck of the jug. In this case, I sorely underestimated volume, so I added almost a gallon of water and 2 lbs of sugar. The water is filtered, then boiled and cooled to lukewarm. The boiling ensures that I'm not adding any additional microbes, and the cooling protects the yeast from being killed off. After adding sugar water, I was back up to a specific gravity of 1.07.
Finally, add the air trap. I filled my air trap with sulfite water (1/4 campden tablet in 1 quart of water) and put cotton in the top to keep fruit flies out.
Shortly after racking to the carboy, vigorous fermentation started up again, no doubt revitalized by the fresh supply of sugar.