I am no expert, but have two older pups and this is what we have found.
10 - 16 wks - Land Sharks, puppy teeth and they put everything in their mouths. Put everything they might eat away. They will try to mouth your hands, arms, legs. Remember they don't have hands so they use their mouths instead. In the 4 - 5 mo the puppy teeth will be replaced with adult, so this faze stops and your scars heal!
5 mo - can be a fear time for some pups. Things that never bothered them before now may be a bit scary
8 mo - ? This starts our latest stage. All the training seems forgotten, counter-surfing, zoomies to the extreme. The more knowledgeable tell us this is the beginning of the teen time. OMG - The most fun, but most difficult. Train, train, fun, fun!! I don't have a clue how long this will last, but Kye is learning so much now and pushing her boundries. She is also the biggest clown, and keeps you laughing a lot.
This is as far as I can say in my own experiences. I am sure others can come here and supply much more. Learn to laugh more, work hard with your pup and it will pay off so much! I know I will miss this time when it passes, but boy the first few years are going to be exciting for sure.
Biggest thing is come here to talk of your stories, learn to laugh will us all cause we have been there and it is great knowing we are not alone.
Someday we will have the beautiful well mannered adults you see here, but all of us had to go through the puppy stage at some time.