Some people assemble it as a unit and then bolt it on, I have never tried that way.
I assembled mine to this point.
https://www.flickr.com/photos/advance-design_parts_co/8129077102/in/album-72157631867396207/
Then added each fender and shimmed as needed to cab. Then I installed the hood.
https://www.flickr.com/photos/advance-design_parts_co/8129073652/in/album-72157631867396207/
Left everything loose when I the installed the repop grill (trust me it all needs to be loose). leaving head light buckets out allows you easy access to radiator support and fender braces.
https://www.flickr.com/photos/advance-design_parts_co/8129183509/in/album-72157631867396207/
Install hood latch and filler, finish all misc and adjust hood (read the Tech Tip) and use another person to help.