OH boy, I cant begin to type out all you need to do, and have it make sense...
I will state the frontend must be put together as a clip and then set on frame and joined to cab. Leave all bolts loose till everything shifts into place. Fenders/rad support/grill/splash shield all together. It will not fall together easily,you will sometimes need to enlarge a hole etc. Doesnt matter chevy metal or aftermarket. Have patience, walk away and come back fresh if frustrated.
Get one of these!!!