Installation of Direct Stream modem

I am a new occupant of this home and I am scheduled ro receive a modem on 11/30. I spent several confusing hours oh the phone setting up this service. I was asked a confusing question about jacks. The home has phone jack because it predates cell. One wall jack is labeled ATT and has a jack that says broadband. Is this at all connected to the installation of a modem? I am old and overwhelmed with this process. Thank!