The enuresis alarm is wonderful for kids that need help in making the association that night time is either for sleep-not peeing, or for waking up and using the toilet if they need to.
At first, although the alarm is on the child, the alarm is for the parent. So make sure you are within hearing range. You will be helping your child repattern associations.
When you hear the alarm go off, you get up and gently hurry your child into the bathroom. After a number of nights of doing this the associations in your child's mind will begin to be made. Although they are sleepy, talk to them, coach them, so they know the pressure in their bladder at night is their body saying "you need to use the toilet." Make sure you schedule a nap in the daytime for yourself for the duration of the training to prevent loosing your own mind from the interrupted sleep. As a teacher, you probably know better than most that praise, acknowledgement, and good concern resolving skills will fuel the hope your child will need to have the courage to develop this new self discipline.
If you are a teacher, there is an excellent book called Raising Self-Reliant Children in a Self-Indulgent World by Glenn and Nelson that you might REALLY enjoy. Another is I Don't Have to Make Everything All Better by Gary and Joy Lundberg. I thought I would mention these as they both contain excellent, communication skill training that in turn fosters incredible self-reliance building in children.