If your monitor and laptop or PC have one or two HDMI ports, you just need a single HDMI cable. If you want to connect two monitors but only have one HDMI port, use an HDMI splitter. Be sure that the splitter has the same refresh rate as the HDMI cable.
How do you connect a laptop to a laptop and use both screens?
Connecting the two laptops To connect the two laptops, attach an HDMI cable to the primary laptop as you would for any external monitor. With many laptops not having HDMI ports anymore, this will likely include using an adapter from a mini-DisplayPort or USB-C port. Connect the HDMI cable to the Video Capture device.