Multiple devices can use one internet plan, but you can only connect one device to the Guest Wi-Fi at a time. If you want to connect more than one device simultaneously, you can purchase discounted internet plans for additional devices.
To switch to using your internet plan on a new device, connect the new device to the Guest Wi-Fi network, enter "login.com" in your browser and then input your username and password. You should then be able to 'Disconnect other device' and start browsing on the new device.
You can also disconnect a device anytime by typing "logout.com" in your web browser's address bar.