Secure Shell (SSH) is a network protocol for secure data communication, remote shell services or command execution and other secure network services between two networked computers that it connects via a secure channel over an insecure network: a server and a client.
Gargoyle is running a SSH server by default. On a client PC install a SSH client to run commands, copy and edit files.
Clients are available for both windows, linux and OSx. The most popular SSH client is PuTTY. If you only want to copy and edit files with a windows interface WinSCP is highly recommended.
This documentation is assuming a connection from a windows machine to a gargoyle router