Your best course of action is to configure your IMAP client to use SSL (port 993) if it does not support TLS. Modern versions of good clients, such as Pine, will automatically negotiate TLS without any need for user action. With lesser clients, such as Outlook, you have to configure use of SSL explicitly.
Otherwise, read the instructions in the BUILD and SSLBUILD documentation files. But be aware that if you do a LOGIN without SSL or TLS protection, then hackers can steal your password and hijack your session.
