Noob Here- Trying to learn how to install openwrt

I am using windows10 trying to install openwrit on a Netgear R6120. I have downloaded Npcap 1.78 and <nmrpflash-0.9.22-win32> as well as <openwrt-23.05.0-ramips-mt76x8-netgear_r6120-squashfs-factory>, but I don,t understand how to input the commands for finding my Ports. Do I use command prompt or the Nmrp file? Neither of then will accept the listed commands for finding the ports. Nmrp just closes at any key press and command prompt just says command not recognized.

Make sure Npcap is installed with WinPcap compatibility mode enabled.

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Open a command prompt in administrator mode and navigate to the folder where nmrpflash.exe is located.

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I had issues with 1.70+. Try to find version 1.60.
If this is your very first install on OpenWrt, installing thorugh nmrpflash is kinda some harsh first time.