Did several Bones...Just got done with a '73 Roadrunners about two weeks ago (that was a little nerve wracking)
Get a small pal of water or a spray bottle and add a few drops of dish soap or use a decal application spray like "Stick on!". Get the car out of the sun and make sure the paint is dirt/dust/wax free. Lay the sticker on (with the backing) to get a good reference where in needs to sit on. Then, get the decal out of the way and wet down the area where you're gonna lay the sticker. The more wet, the better. The more solution, the longer you will have to position the decal into place. Pull off the backing and apply the vinyl sticker. With there being a layer of solution underneath, you are now able to move the decal around into place. Once you have it in place, I use a plastic body filler applicator with a thin micro fiber rag over the top (so not to hairline scatch the sticker), and gentley start to squeegee out all the air bubbles and water. No need to press hard. Keep in mind, once you start to squeegee out the water/air it's going to get harder and harder to move the decal...Trying to peel the decal up after it's seated usually leads to you streching the sticker, thus...well....a disformed decal.
Squeegee out all the bubbles...If you end up with a small air bubble or trapped solution here and there after squeegeed out, no big deal. Again, don't try to peel the vinyl decal back up if it's seated well. Odds are you will warp/stretch it. Use a fine point needle, prick a small hole and then work out the solution/air with the applicator and or your finger if it helps. Also, a bask in the sun after may help flatten them out.
That's all there is too it...If you have the opportunity to practice on something else first, I would being you don't have any experience with them yet. Probably give you a piece of mind and you'll see it's really not that hard.
Good luck