If your screens won't turn on then you first need to check your connections.
- - Make sure that you have BOTH a video AND power feed going to each screen. Unless your laptop has a USB-C with Display port or a Thunderbolt 3 port you will need to use 2 cables per screen to it to function. (1 HDMI video cable and 1 USB-C cable power)
- - If you are using a USB-C port on your laptop along with a single USB-C 90 degree to USB-C cable for power and video, make sure that your laptop supports video over this USB-C port. Search for your laptop user manual online for these details.
- - If you are using a USB splitter or USB-Hub try plugging the cables directly into the laptop ports instead of the hub or splitter and see if that fixes the problem. Most splitters and hubs split the power from a single USB port thus restricting the required power supply to each screen.
Next, make sure that you are using the correct combination of cables. Read through the section above for more info on the correct cables.