@HimWho,

The IoT Network is a completely separate SSID being broadcast, so you would need to reconfigure the network settings on your Smart Home Device and App to connect to the IoT Network SSID. 

If you are looking to isolate the device from your main network, you would need to do this from the Device Isolation settings, rather than by simply moving the devices to the IoT network. The Device Isolation feature works across both networks. Lastly, please remember that the IoT network does not automatically isolate your devices.