Blue LED indicator shows you the working status of the switch. Your switch is always by your side. Power on electricity, press and hold the setting button for 2 seconds. When the indicator light flashes, it enters into matching code mode, then loosen your finger.
Switch AND tranmitter in this item. I had previously bought a unit that included both switch and receiver but when I ordered a second item from that suplier they no longer include the receiver which I failed to realize so I came to E Bay to find both in one item and wish I would have done that to start with