In order to use it, however, you'll need to log into the accounts for which you have two-step authentication enabled and change the method you use to receive the shortcodes. Unsure where to go? Read through this post, which walks you through most of the major services' two-step setup process.
Alternatively, we have a solid guide for switching Google Authenticator from one phone to another, and wouldn't you know it? The same applies to changing your setup to another app. You'll need to have a browser window pulled up on a computer and be logged into the respective settings page for each service before you can switch over to 1Password.