They are really easy to install. The scary part is drilling the holes in your hood. Take your time...
I have always attached them to the crossmember that the hood latch is on. It's metal, it's welded in and it has been holding the front of the hood down since the day the car was built.
First figure out where you want them to be by looking at your hood. I usually go about 6" in from the fender but your car will determine what would look good. Then establish where to drill the holes in the crossmember to match the width you like - measure and remeasure to make sure they are exactly the same distance L/R and F/R on both sides. It would be really hard to convince people that you deliberately installed your hoodpins with a L/R or F/R offset.
Make sure there is nothing behind the crossmember - like the hood release cable - and then drill the holes in the crossmember for the pins. The pins are threaded at the bottom and are held in with nuts and washers top and bottom. You will probably need to play with the hight after the hood is finished so don't worry about tightening them very much until the very end.
Now your ready to drill the holes in your hood...take a deep breath, close your eyes...no it's not that bad. With the pins installed as above you need to determine where they make contact with the bottom of the hood. I use some small pieces of putty or paint, just make sure to get the paint off of your nice new shinny hoodpins before it dries. Lower the hood until it contacts the pins and when you lift it up you should know exactly where to drill the holes.
The hoodpins come with shinny round discs with holes in the middle that you screw to the top of the hood. Make your holes in the hood a slight bit bigger than the holes in the discs. Drill the holes, screw the discs onto the hood, adjust the height of the pins so that they are not sitting up too high but are still easy to get the latch into.
The latches come with vinyl covered cable to attach them to the car. I usually cut the cables off and just use the latches. I also carry a set of pad locks that can replace the latches as an additional anti-theft device. An added little bonus.
