I'd second Jeremiah's advice. As for aftercare, I've left collected junipers outside in shady spots where they got filtered light, under shade cloth, and in a greenhouse. All did pretty well though I haven't done enough to say which approach is best. My guess is a greenhouse with good ventilation.
The most important thing after collecting is lots of overhead water or mist without keeping the soil too wet. In general, the roots only need water when the soil dries out. The foliage can be misted or watered many times a day, depending on the temperature and relative humidity.