If you were near Maidstone I would come and help you, I've recycled 3!
Clean it first, it is pain doing it later, use a kitchen scourer or something quite abrasive like a fine sanding block with lots of water.
Identify the bits, the angled ends give a clue to where they go.
The apex (top of the roof) goes in from the inside.
The rubber gasket is not essential but is recommended, you can buy a roll of it from Halls etc if you are missing lots of it.
Obviously the glass goes in from the outside, start at the bottom and do the entire row then do the second row followed by the roof, first row then second.
The 'W' clips are quite sharp but I find it easier to use fingers rather than pliers. Put one prong into the groove in the frame, push the flat part against the glass and then clip the other prong into the groove.
Good Luck, it is really not that difficult.
