Load your shots in a syringe. Depress the syringe to relieve the air as you don't want to inject air into the dog. I usually wait till feeding time, and while the dog has his head in the bowl, pull up gently on the loose skin on top of the neck. Come in with the needle at about a 45 degree angle from the top and inject the vacine under the skin.
Most dogs act like they never feel it......others, cry.
I'd give that vaccine every 2 weeks until they are 16 weeks old, then again at about 5 months, then annually.