I have kept a Sony Betamax SL-C20UB with original box and instructions since 1984

About ten years ago, I paid roughly my 50+ Betamax tapes to be converted to digital files and the video has been unused since

I am now looking to sell it and want to test it first, by connecting it to my LG55UH650V WebOS SMART 4K Ultra HD TV

Unfortunately, I am confused by the cable configuration, in particular the video in/out which I believe needs a "BNC to Phono cable"

Could somebody please explain what I need to plug in/out of the video and the TV to test the video?

Thank you