Hi last time I want write my own Messenger client, but in documentation I see only information haw to write chatbot. But I know that it is possible because I found something like this Messer - comand line client.
I tried to understand how it works, but I am not good in JS.
Anybody know how it works, or maybe have any article how to do something similar?
First of all tools like the one you linked violate the FB policies and will result in getting your account banned. So if you are asking "how to do something similar" you also will most likely violate FB's policies if doing something "similar".
You can look into using the official Messenger Platform API instead: https://developers.facebook.com/docs/messenger-platform/