If you want to turn on the wifi go to the device, remove the faceplate and with a small object such as a paperclip, press the AP (Access Point) button (as shown in the image).
On the app, either you already done the registration once or you skipped it at the beginning, you need to add the device as a new one. To do so go to My devices and click on the + you find up on the right and follow the procedure.
In case you already did a registration in the past, once you restore the connection you’ll find all the preferences as you set them.
Then after you attached the face plate restart the device from the device setting on the app in order to re calibrate the touch.