How does Twitter work?

[Googleâ„¢ me]

Direct Messages - You can only send messages if both of you are mutually following each other (i.e. you follow him, he follows you)

You can get the person's attention by starting your tweet with @person's username. This will show up in their Mentions section of their Twitter.

You can't force people to follow you. In order to have someone follow you, you have to be engaging and interesting. When you follow someone, their tweets will show up in your timeline. If that person asks a question or says something funny, you can then reply with an answer. Hope this helps.