this is a job and well worth the 100$ an upholstery shop will charge to replace it
alright with that said, you have to unbolt the window in the rear and unzip the old window remove it out of the way. now you have to unbolt the sides of the top where it wraps around the car. then you will peel the top forward to expose the area where the fabric attached to the zipper is located. you will have to pull the staples and install the new strip(make sure it will be center when installed). the staple are short and the staple gun has to be able to fit down in the recessed area. after this is done you reinstall the sides of the top by bolting them back down.
now the bottom of the old window must be removed from the lower bolt in strip. then you will need to center the top so it will line up with the zipper and the lower strip and have enough fabric to make sure the window is snugg. then you will need to mark the window where the strip need to be. remove the window and staple it into the strip and cut out the bolt holes in the fabric.then zip it in and bolt the lower in and thats it.
but seriously its really aggravating imho id pay some 100$ well worth it