I've installed them before and there is a lot of trial and error,first get a name brand product......US Body Source or Glastek are quality. Second get reliable help,make sure they are in it with you till the end of project,not "Hurry up,I gotta be home at 6:00,my wife gotta go to Walmart!" I went thru that crap before and you don't want to rush. Take your time and read directions,mock it up a few times and so on......sometimes it took me a half of a day but if you get tired,cranky,and start cursing.............close the door and do it another day. This is just my opinion but it usually works.