@mrtim 

During the set up it will ask you to choose which WiFi network to connect to and it should give you the option to use your saved network

  @mrtim 

I would recommend switching to the Tapo app. You will be able to control all of your Kasa devices in the Tapo app as long as you use the same email and password you use to log into the Kasa app when you log into the Tapo app for the first time.

Once all your Kasa devices are in the Tapo app you can safely remove the kasa app :) 

  @mrtim 

Almost forget this. Once you log into the Tapo app click on "Me" from the bottom menu then click on "Link Tapo With Kasa"  then follow the one screen instructions :) 

  @mrtim  The Wi-Fi network information saved during device setup is stored locally in the app and will be removed if the app is uninstalled. If you haven't configured a device with the Tapo app before, you'll need to manually select the Wi-Fi network and enter the password when setting up a new device.