adding instructions on signup register page

Hi,

When a new user registers on the login/register page provided by the classifieds plug - the user registers and then nothing happens. No message to say it was successful or that they now need to look in their email for registration link and password. etc.
For some users coming to the site this may be fine but there will be others who won't understand. My question is - can I add some instructions somewhere without having to do this again every time the plugin updates. Or have I missed something somewhere??

Ideally a message should appear to tell the user to check their email and then come back to login.

Any help would be appreciated with this.

Jo