The screws are under the rubber gasket. Start by removing the sheet metal screws that hold the front of the gasket at the base of the A-pillar, then pull the rubber gasket out. You'll have to remove the gasket channel first, and then another set of screws holds the gutter sections on. Pay attention to which screws hold what, and you might want to measure how far in or out the channel is so when you put it back on, the windows hit the gasket in the right spot.
Removing the windshield trim is explained in another post right by your's.