sendmail

Hi, I am pretty new to all of this so please be patient. I am trying to use sendmail so that when a character is created in a game the character will get a email with there password. that's the idea any way. Howver I can't get sendmail to even send a e-mail threw the command prompt. I have tried and tried to find out information on how to set it up to configure it and keep coming up with the same thing. it isn't working. Please some one if you know of a place that can give details on how it should be set up or can tell me how to that would be extremely helful. I am using Ubuntu 14.04, and did the apt-get install sendmail. please some one help. thank you in advance.