IMO, you really did not choose the most optimal time to add a Doberman puppy to your family and you really are going to have your work cut out for you.
I've owned and loved Dobermans for 26 years so it's not like I'm biased against the breed. It's just that Doberman puppies tend to be rambunctious little monsters at times. It's almost a given that your child is going to get hurt unintentionally be it scratches, mouthing or being knocked over and then you're going to have your family all over your case.
When puppies are teething, they will mouth everything and that includes your child. You are going to have to be extremely diligent about ALWAYS supervising EVERY interaction between puppy and child. You never know when they are going to lift a mighty paw and give an unintentional paw to the face. One of my 11 week old puppies jumped enthusiastically right into my nose yesterday when I was bending over for something, caught me right off guard and yes, it really hurt. I'm an adult. If that happened to a kid, it would have been screaming bloody murder. Doberman puppies don't seem to recognize that they are getting bigger, have a total lack of body awareness and your kid is going to get knocked flying.
It's truly one of the reasons why I don't know many responsible breeders that would place a puppy with a family with really young children. As I said, what the Doberman does is going to be unintentional but your family is not going to understand that, and neither is your child.
As for the dachshund, same thing. Dobermans like to play rough. I hope the Dobe doesn't unintentionally step on your dachshund's back. You've got a breed that needs some care there, and a young, rambunctious Doberman puppy may hurt the dachshund. Overall, I'm not a fan of mixing small breeds with larger breeds. Dog spats happen, you never know when, and I just think that the small dog doesn't have much of a chance if something really decides to break out between them. I hope they aren't both males?
You don't need books and videos. You need a qualified obedience instructor in a class setting.
I see we've got some people trotting out the old "a tired puppy is a good puppy" cliche. A tired puppy is a tired puppy. A trained puppy is a good puppy. Don't mistake exercise for training. They need both.