Use the grey space at the bottom of the screen to tap. Avoid tapping in the middle, where you may obstruct your view. Each tap changes the direction of your character. You must finding the proper rhythm and stay with it to remain in control. A longer tap will break that rhythm. If you tap too fast your character will move in the opposite direction. Use two fingers to control your character, one to the left and one to the right side of the screen. Have each finger control a direction change, so that when you tap with your left finger, the character moves to the right and vice versa. When launching the character always moves to the right, so start with a left finger tap. Quick tapping seems to result in better control, but two fingers are required to keep the proper rhythm. Start slower until you get used to controlling your character, then progress to a faster rhythm.