The Ultratronics board can be connected to the Nextion displays using the Serial2 pins. This allows you to easily add a LCD with touch screen function, without impacting the performance of the 3D printer, as the Nextion takes little CPU power away from 3D printing.
The Nextion LCD comes with a cable that connects on one side into the LCD and at the other side has four strands:
Connect the colored wires as shown in the picture. After connecting the wire the electronic setup is done. Now proceed with uploading images to the LCD.