There is a "U" shape rubber seal that first goes around the window itself STARTING at the top center and ending at the top center of the window. Originally the two ends were, I think, stapled together with a peice of friction tape covering the staple...at least that is how it was on my September 1929 Standard Coupe.
This goes for the rear window also.
The window is then inserted into the quarter window area on the body.
It is then followed by the quarter window trim which is screwed at various places on the wood peices surounding the quarter window with wood screws.
You will notice on the trim peice that there is kind of a lip...this lip holds the upholstery panels in place when fitted to the body and tacked into place.
You might want to put some sealent around the windows before inserting them but not enough to allow the sealant to ozzz out and around the seal on the outside of the car.
If you do however, you might find that it is kind of hard to remove if you ever did so.
I never did however and have had no problems with leaks.
Pluck