put the screen screenprint-way up, so any drips that happen will make bulbs on the bottom which touches the shirt, and not on the side you're going to squeegee.
Develop it: 1 min summer, winter maybe 2 minutes. Put plastic or glass on screen, for weight (you don't want light under the film). And put something around the bottom so no light comes in underneath.
Blow off the dried emulsion with a garden hose with pressure.