If your disc brake is rubbing, you can easily adjust it. We are in process of creating a video for it. In the meantime, have a look here: https://www.youtube.com/watch?v=l4hgbV_Hb7g (minute 1:40).
You loosen the two top bolts without unscrewing them. pulling the brake will center the caliper over the disc. snug the bolt, release the lever and check if that resolves the rubbing. If it does, properly torque the bolts to 6 N.m.
In order to adjust the distance between the brake pads, use the small screw sitting on the side of the caliper. See picture below.