New Post: Can't see where user add their information for sending a tweet

Hi at all, I just start using the Tweetinvi API for my next Metro Application. First of all i downloaded the sample and i tried to understand where the user insert their username and password for sending the tweet with their account. I red code for an hour but i can't see anything. Could someone help me. In my app I need only to log into the account and send a tweet.

Thanks in advance.