Open the Wireless Display app on the laptop you're using as a second monitor On your main PC, press Windows + K to search for wireless displays. Select your laptop's name from the list of options.

I urge those considering a second monitor to try virtual desktop tools first and plan exactly how you’ll use that second or third display! 5 Reasons Why You Don’t Need a Second Monitor on Your ...

Once you have got your hands on an HDMI capture card, connect it to the laptop you want to use as a monitor. Then, connect the HDMI output from your main computer to the HDMI input on the capture ...