The Guardian should open the invitation link on her/his device. If they have already installed Vault12 Guard, then when they click on the invitation link, the Vault12 Guard app will open and will present a screen asking the Guardian to confirm that they intend to guard the Vault. If Vault12 Guard is not already installed, then the first time the user clicks on the invitation link, they will be encouraged to install the app. Later, after successfully installing the app, they should click on the invite link again so that the Guard app opens and presents the Guardian with the confirmation screen described. The app will also ask for permission to "Allow Notifications," which will support timely interactions between the Guardian and Vault12 Guard in the future.