If you're talking about the belt molding that runs horizontally along the bottom of the window there is one screw and some rivets used as guides holding it to the door. Open the door and look under the rear end of the molding. Under the lip you will see a small screw. Remove the screw and slide the molding rearward and it will come off.
Just be careful to pull to the rear of the door without putting any pressure on the moulding. You do not want it to scratch the paint of the door. Once you bring it back so far (1.5" maybe?), it then just comes straight up off the plastic "buttons".