How do I reset my LG Smart TV to factory settings w/o remote

I can't figure out how to reset my LG smart TV back to its original factory settings. I need to do this so I can reset my network settings and connect it to wifi.  

When I go to the network settings, the actual settings button on the screen is greyed out only giving me an option to test or close. 

It was my father's. It's been locked away in storage for over a year now since he passed. I don't know any passwords, or have the original manual ,or even the original remote, or books the tv came with. I did go buy a universal remote tho. Any tips, steps or suggestions are greatly appreciated.