Getting it on the glass isn't a big deal, but you have to make sure you match the corner angles correctly, as one has a more acute angle than the other. Once you have the seal on the glass, you can spray wd-40 in the frame, and start sliding the glass into it, when it starts getting stuck, spray some more wd-40, then lift the frame up by its sides so that the pointed end is pointing down, and lightly tap the point on a padded but firm surface - I used a table with a bath towel on it. Tap the frame to the table a few times to seat the glass and seal into the end. It has to seat ALL THE WAY or the end piece will be impossible to fit properly.
I spent almost three years trying to do this properly, and went through 2 full sets of seals . I used the URO seals for the first attempt and never got there. I used Authentic Porsche seals for my last attempt and finally got the windows to fit the frame. It was very frustrating.
The outer frames were much easier once I discovered how they press in. But it took a couple years to figure it out. You have to make sure both sides are inside the frame rails, and then you need to press in on the center of the seal all along the entire edge until you hear a pop that indicates that both sides have clicked into the slot they are supposed to seat in. The window just plain will not fit if the seal isn't properly seated all around the window.
To complicate matters, the tabs that go on the straight edge need to go in in the correct orientation, or the window will be at the wrong angle to the frame and it'll never fit. Problem is, I don't remember what the orientation is right now
