The molding around the whole window on the rear outside must be removed . It extends almost 2" in to the roofline and wraps around the inside back above the engine lid.There is also a rubber gasket there that you will also have to replace.
I had to replace mine a couple of years ago. I had a hard time finding one. I found 3. 1 was $1.600.00. another, $1,400.00 and the last one was $800.00...I went with the tha last one...fricken ridiculous
have fun...
Oh and welcome to TN...