Its a bugger of a job you need for hands but first look on each end one will have the adjuster bar put s/driver in it push in and turn clockwise I think to tension then release when in line of the locking shaft you pushed it out of. If you have to take it off then when replacing tape the side runners to the roll frame once the tops are fitted in slot and offer back into bottom bracket screw roll blind top screws in ensure the blind and net if fitted are in correct chennels.
Open the window wide as if you loose your rag when doing it you won't break the window throwing the screwdriver.
Bob
June 2009