You'll be prompted for the name of your host, the ssh user and the port that should be used to connect to the server and which checks it should run.
On most systems the authenticity of the host will be verified when connecting to it for the first time. To avoid problems while running the check we recommend manually opening up an ssh connection to the server you want to monitor to get past that check.
Although we don't recommend this, you could opt to disable the host authenticity check altogether. Be aware that this will leave yourself open to man in the middle attacks. If you want to go ahead with this option add -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -q to the ssh_command_suffix key in the server-monitor config file.
You can also prefix the SSH command. Just add your desired prefix to the ssh_command_prefix key in the config file.