[Alug] Can anyone help me with SSH please?

My web site hosting company have just changed from Telnet to SSH. I am unable to establish a connection and I'm not sure quite what I'm supposed to do at my end. I'm running Debian Potato and have installed SSH. Do I need to do anything else in order to use it? I have looked at the man page but, as always, I don't understand it. SSH appears to connect to the host but exits with 'secure connection refused'. Any help gratefully received. Barry Samuels