Always soften gelatin in cold liquid first, for about 5 minutes, then dissolve in hot liquid. Don't really boil or you will reduce its jelling power. Allow at least a few hours for a gelatin mixture to solidify, overnight if the mold is very large.
Use 1 tablespoon of gelatin to 2 cups of liquid. You can mix this with 1 – 2 cups of solid ingredients.
To loosen from a mold, first go around the top edge with a sharp knife. Then heat some water up, making sure that you have enough to come up the sides of the mold all of the way up to the rim, when you place it in the water. Dip the mold in the water for a few seconds, then cover it with a serving platter or a large plate, depending upon the size of the mold, and turn it over until the dessert loosens. If it doesn't loosen immediately, let it sit for a while.