To start with, click the coin until you have 50 coins. This will automatically cause the egg to start hatching. The poke ball will announce the random pokemon you received. Whichever pokemon you got, it will give you a number of coins per second. Click the berries(oran and razz berries) to open the berry store. Each basket of berries will cost 1 to 10000 poke coins, but will add up to 10000 coins per second to your ever-growing coin collection. Every so often, the egg will hatch again, at no cost, giving you another pokemon. Keep on collecting pokemon!