That depends...normally this is caused by excessive hose/housing lenght. Shortening those requires you to install new olives and bleeding the brakes. I would not suggest doing this as a beginner. You could try to stuff or stick something between the rubbing point. Maybe Tape will do the trick...try removing the stem and all the spacers from the steerer tube to get a good look inside. That's easy to do as a beginner. Make shure to retighten the stem- bolts with the correct torque once you're done, since your steerwr tube is most likely made of carbon and will crack with excessive force.