This article explains how to connect Alexa to Wi-Fi for the first time, plus how to change Wi-Fi networks for an existing device. Instructions apply to all Alexa devices, including the Amazon Echo and Echo Show.
You should have downloaded and installed the Alexa app by now. If not, do so via the App Store for iPhone, iPad, or iPod touch devices and Google Play for Android.
If this is your first Alexa device, you may not need to complete steps 2-4 below. Instead, you'll be prompted to begin setup once the app launches.
Enter your Amazon account information and click Sign In.