Most young creatures of any species aren't born with off switches, we need to train them!
One of the most important things a puppy (or kitten! Or toddler!) needs to be taught learn is how to be calm and relaxed. An "Off Switch" isn't something most young puppies come already knowing.
This little pup is Pretzel and he is a go-go-go kind of pup but it is hot-hot-hot so hanging out (in the AC!) to practice a down-stay for 30 minutes is a great way to get some computer work done while exhausting him mentally. After a potty trip outside, he found a comfy spot and slept soundly for an hour. Its hard being a baby Yorkie.
As you can see Nike and KitKat are masters at the chill out time.
Puppy doesn't know how to hold a Down? Look into the "Sit On The Dog" technique for helping to condition calm when the vocabulary is still being built.