anyone know where can i get assembly diagrams for basically the whole front end: bumper cover + passenger fender+ bumper + ground effect + radiator mount. basically everything. Any guide that shows how to put one together or gives a visual picture would help. GM dealership maybe?

Try the factory service manual and parts and illustration manual.

FBodyCD.com, it's one of the sponsors.

It's also one of the most useful tools you can have for your car.