BATTOP 2.4G Portable Wireless Numeric Keypad for Laptop Notebook with Receiver&Built-in Receiver Storage-White Open the rear cover of the keyboard, install one AAA battery(Not included the package, Note the positive and negative directions), The red light will be lit and then extinguish. At the meantime, pls kindly remove the receiver,Insert it to the devices USB interface, and then computer will install the driver automatically, Finally, you can use this Numeric Keypad. Red light on,digital zone function is turned on (Number 0-9) Red light off, arrow function is turned on ()