Sedan Door Glass Installation Question

i just did this, the glass goes in the rear track and you have to put the vent window in at the same time as feeding the glass into the track. its not easy to line up at first. i rolled the glass up n down till it was in the right spot. i know people who have broken the glass trying to get it right. i had to stop and take a breather a couple times to get it right but it actually goes in without too much fight. good luck