Here are some good links.
Step by step instructions manuals with pictures 
Watched a one guy install a door during lunch once.
He did it in less than 30 minutes .. no joke.. mind you this was new house.
Starting from the bottom he threw the door pieces up, tacking them with 8p nails.
Lining them up on one end.
tack screwed the the hinges in place.
put the side rails in position with the wheels.
tacked it all together.. and put the top rails up swinging free.
Started pulling the door up to line up and straighten the top rails.
Installed the braces to the top rails and then opened it, closed it a couple times and then screwed the whole thing off.
installed the spring.. done.
Totally amazed.
Then took a good hour to clean up and eat lunch.
Framer