Slide the glass door panel closest to you so it is in approximately the center of the track from side to side.
Grasp the panel firmly on each side with your hands.
Lift the panel straight up so the rollers at the bottom of the door clear the track at the bottom.
Swing the bottom of the door toward you and away from the track.
Lower the panel slightly so the top of the door clears the upper track.
Remove the panel from the bathtub.
Repeat Steps 1 through 6 to remove the remaining glass panel.
Install the glass panels in the reverse order of removal.
Loosen and remove the retaining screws from either side of the top track with a Phillips screwdriver. Lift the track straight up from the two vertical sections of track and remove it.
Remove the retaining screws from the inside edge of the two vertical end pieces. Pull the end pieces away from the edges of the wall or tub surround, and remove them.
Lift the bottom track straight up from the top edge of the tub and remove it.
Scrape any caulk residue from the tub and surround, using a plastic putty knife.
Fill the screw holes where the vertical end pieces were mounted, using caulk.