Fill up the pot/bowl/container halfway with small pebbles/rocks/marbles and then place your paperwhite bulbs root down on top of the pebbles and start filling in the rest of the pebbles leaving about a third of the bulb exposed at the top.
Fill your container with water just so the very bottoms of the bulbs are wet (not soaked though, if they're in too much water, they'll rot). Now you're good to go and should see some sprouts in about a week.
Monitor the water level and add it when necessary over the next couple of weeks.
Paperwhites will end up growing anywhere from a foot high to over 2 feet and can sometime fall over from their own weight. We read recently that if you use alcohol you can actually stunt their growth to keep them small.
Are you planning on planting some bulbs this winter?
[Image from Karen P]