[otrs] Responding to users via OTRS.

Hi, all. Maybe I'm just dumb, but I haven't figured out how one uses OTRS to respond to users. One "problem" with OTRS is that it's got so many features, it can sometimes be daunting to find the answer in the documentation. I've tried, for example, to see if "note" would respond to users, but it appears not to -- though the fact that I only have "note-internal" in my drop-down might be relevant... but I can't figure out how to modify that. So, bottom line, if there's a pointer to what I should be using, it would be much appreciated. Thanks, -Ken