In the 1st step, it directs:
“Copy the syncthing binary (the file you would open to launch Syncthing) into a directory called bin in your home directory i.e. into /home//bin. If “bin” does not exist, create it.”
So, by using Terminal, I tried the next command:
sudo mkdir /home/GundamSK/bin
where GundamSK stands for my username, and next typed my password.
But Terminal answered as
Operation not supported
I don’t know why it says operation not supported. But do not use sudo. That will create a directory owned by root which is precisely what we want to avoid.
You can create the directory in your home directory using the Finder, as usual. Or, open a terminal and type mkdir bin (it should start in your home directory).
Your home directory is /Users/GundamSK/, not /home/GundamSK/, somewhat explaining why you get the error message.
Apart from that, Jakob has the solution.
I read wrongly the meaning of my “home directly”.
Following your advice, as I made /Users/GundamSK/home/bin/
and copy the binary of syncthing,
everything is now OK.