Window replacement trouble

[wayzhack]

Hey guys, I just joined and this is going to be my first post, and its a bit of a long winded stupid question but here goes:

I need a bit of help here... I recently bought a rustless 1988 Toyota Supra Turbo shell, and I am trying to fix up the body so that it will be ready when I get my engine (7mtge). Currently I am trying to replace the driver's side window glass but I am having some trouble.

I cant exactly get the glass to go into the door frame... I have tried turning it different ways and putting it in from different angles but I have had no luck. The car has power windows and they are set to the "up" position, but there is no engine and battery so I cant lower the rail to get it into a better position. There are also these white nobs on the glass which prevent me from easily inserting it into the frame.

Im just looking for some advice or tips on how to position the glass to get it into the frame and attached to the door.

I know that this post was too long and kind of repetitive, but I just want to be as clear and throrough as possible and get a good answer.

Please help if possible!