First,you need to download Alexa app.

Go to alexa/amazon com and easily download Alexa app & install the Amazon Alexa app on your devices. 

Fast Plug in Amazon Echo Dot.

After that select your Amazon Echo Dot device & connect Echo Dot to WiFi network. 

Echo Dot setup is complete.

Your Amazon Alexa app ready to work.

You can ask for Alexa about news, weather, location, watch movies, listening to music and many more.