how to replace rear triangular window (quarter glass), please help

some dumbass so it fit to break in...2002 chevy tracker (probably same on most cars)...cheapest shop wants $150!!!!!!!!!!! i could understand the price for a powered main window, but this little piece?
do i just remove the inner door panel...it seems one could just take the molding out then and put the new one in easily....
thank you!

replacing those quarter windows is like replacing a windshield. If you have no experience have someone else do it. 150.00 isn't bad for that replacement and you will have a lifetime warranty against leakage.