A mushroom's life begins the day the spore touches the ground. The spores then work their way down into the moist soil. As the spore sits there the rainfall and sunlight helps the seed to germinate. Germination is when the spores start to grow little roots. As the roots start to grow, so does the plant. 

As the mushroom starts to grow, it grows stronger. Soon you will start to see a button. A button is when the mushroom has started to pop through the ground, all you will be able to see is the cap.

A few weeks later you will start to see the cap get bigger, and the stem will become visible and taller. The mushroom will also start to develop a ring. In a few more weeks the mushroom will be full grown.