Step 1:
Press and hold the button for 5 seconds until the LED light flashes blue to enter pairing mode.

Step 2:
Say to Alexa Echo: “Alexa, discover device.”

Step 3:
In above a minute, Alexa Echo will discover the Smart Plug.Echo will give you a voice notification, saying :”Found the Plug”.

Step 4:
You can control on/off, group control, scheduling, timers, renaming, and more via voice commands or the “Amazon Alexa” app.
OR  
Tips: If pairing fails, start pairing again from step 1.