If you are connected to internet, your device must have an IP address, if device is Linux system, to know this address, run command on linux terminal.
putty generally is used for ssh/sftp connection.
Default port for ssh/sftp is 22
You must have other users on Linux system, if not, you can create using useradd command.
Now if you want to log into one of the user's account using putty, you can fill above details.
But if you are already using linux system, you do not need putty, you have terminal. Putty is generally used by windows user.