Download Amazon App and sign in here. Now go to the top left corner and find the + icon. Follow the instructions shown on the screen and add your device to the app.
Tap on the exact model of echo that you wish to set up, then click on it to get it. Amazon Echo is ready to Setup.
To get more benefits from Alexa App, you can also go for Amazon Alexa app, Alexa app for pc, echo dot setup, amazon echo setup.