How can I use this LCD TFT screen as a (wired) second display for my Windows Laptop?
That's not what you would really define as a 'monitor'. It would best be described as a 'TV' without a tuner.
It takes composite video, which is a rare output from a computer these days.
As mentioned in comments, you can get an adaptor.
I'd save your money & get a second hand 'real' monitor instead. The picture quality on that screen will be poor, at best.
From the advert - the screen resolution is a meagre 480x272 - your laptop will be at least 1920x1080 I would think. That's not even old analog television quality, it's about half your old "big TV in the corner that took up half the room" quality.
Avoid this product. Please.
Your monitor accepts a composite video input. This is an older analog standard that was pretty ubiquitous on TVs, VCRs, and DVD players in the late 80's and throughout the 90's, and is probably not as common as it once was. I'm not sure composite video output was ever common on laptops or graphics cards.
But there are dongles that convert from any video standard to any other video standard these days. And there is such a thing as an HDMI to Composite converter. Just enter "HDMI to Composite (RCA) Converter" in your favorite search and you'll see plenty of options. This is the first thing that came up in a search, but there's no model number or anything and I can't vouch for it. Just an example.
Note that you'll have really low quality with this, but it should be fine for watching video or possibly playing old games in emulators.
Why is composite low quality? Composite combines the color information and luminance (brightness or black-and-white) into a single signal, which has to be "extracted" by the other end. The color information distorts the luminance information, resulting in color fringes, colors that don't look good next to each other on the same line, and high-resolution black and white stuff like text smearing into color. The Wikipedia article on composite artifact colors explains.