Headlight assemblies mounted loosely, so they can be centered after grill is installed.
Then bumper, and last, valance.
I would also pre fit valance with everything off as the mount points might need some tweaking. Hard to do on your back when you can't see, and are reaching in. With everything off, you can reach right in on the valance.
Don't forget the semi flat black paint first.
Yes, you need black out paint on the front radiator yoke. To describe how to spray it on, some poor sap stood in a pit under the car and sprayed it up at a 45° angle! I sure hope he was paid well or his co-workers at least bought him a beer now and then after work!