Internet self installation

I just ordered the self installation kit and how do I know it will work? When I was on the website it said I have service available to me at my house and I've had Comcast in the past but I do not have any boxes attached to my house that say Comcast or Xfinity. Looking at the pole outside the cable line runs from there directly into my house. Currently I have AT&T internet thats DSL but also has a what looks like a coaxial cable. Is that cable my main line? I'm wanting to put the router / modem in a bedroom away from where that current AT&T one is. I have access to the cable that's running from the line into my house in my basement. I'm just wondering how it all works I want to be certain I'm doing it proper. Once I know it's working, im going to be canceling the AT&T service.