You can choose your donation project to by entering the serial number on http://waka-waka.com/sharethesun/. The number is written on the white sticker located on the hinge of the Power+.
If you don’t see a serial number on a white sticker, there probably is a loose leaflet inside the packaging case with your Share the Sun donation code in case of the WakaWaka Power+ or at the plastic packaging of the WakaWaka Classic Light. You can choose a project on http://waka-waka.com/give/.