The control keys for the keyboard are
FN+TAB= USB/Bluetooth Mode switching FN+[{=LIGHT UP FN+]}=LIGHT Down FN+WINL= Wired Mode All key Unlock/lock FN+Space= Backlit Change FN+TAB= Desktop computer FN+Q= Laptop FN+W=Tablet PC FN+E= Mobile Phone
Try using the lighting options. If nothing seems to work, return it or contact the vendor support. Although for those generic Chinese brands you may have some issues getting anyone to answer support questions or even finding a place to ask them.