Take a deep breath, and relax...
You have come to the lake hoping to see a rare and beautiful sight. The lilies of the lake only open their blossoms in the rain, and only rarely do all eight kinds of lily bloom at once. The goal of A Gentle Rain is to place the lake tiles in such a way to cause all eight types of lilies to bloom before you run out of tiles and the rain ends.
Place each new tile you draw next to a tile already in play, making sure to match the colors of all the tile edges touching the tile you are placing. Each time you manage to complete a square of four touching tiles, a blossom opens between them.
Keep Score, or don't.