just put it on low and don't let it blow directly on the little sprouts, you'll know cause it'll move and try to blow over

i've noticed that the first week of growth occurs mostly in the dark, when it has time to rest as torog said, but keep the dark fairly minimal for the next 6 weeks or so (6 hrs dark per day for about 6 weeks is a good way to remember)

you can get a timer that will switch the light on and off for you if you don't have that already