To use the feature, you need to first install the app on your Android smartphone. Presently the web client feature is only available on Android, though the app itself is available on iOS.
After installation, you need to set it up as you would any other messaging app. however, unlike other messaging apps or a variety of Google services, Google Allo does not make use of your Google account. Therefore, it cannot collect information you already have on the internet. You will need to manually confirm your phone number take a profile picture and give Allo permission to access a number of features on your device.