There is a button on the base of the ball. This is a slide button. Depending on the way you hold the product, the left position is RGB (Red Green Blue, Aka. Color Changing). The centre position is OFF. The right position is white. (Refer to image below). You need to make sure that the button is in the OFF position, and fully charge the solar light for a minimum of 2 sunny days. After the light(s) are fully charged, simply push down button to left for colour changing, or to the right for white.
A video can be found here on how to turn on the solar crackle ball light.
You DO NOT need to remove the screws from the base of the product. If you need to change the battery, remove the stake, and you will see a compartment where you can insert the battery.