I never quite got used to using a crate (they're so BIG for a doberman)...but it is the best way to go
like everyone else says.
But we always gated off an area, usually the kitchen, and puppy proofed it. In my various houses, the pup could still see what was going on in the den from the kitchen. But whenever I could (almost always), the puppy was out in whatever room I was in--watched CLOSELY.
If I couldn't watch him (concentrated eyeballs on puppy at first...catching them before they ever have any accidents in the house is the way to potty train), was doing something where I really didn't want his help or if I was out of the house, they were in that puppy-proofed place. They also went there if they were getting wild and bitey and not able to stop (overtired syndrome)--often that kind of behavior meant they just needed a nap and were too over-stimulated with me in the room to stop with the shark teething.
At some point, probably around 5-6 months, they were allowed out in one room alone (mostly dog-proofed, but, you know, still with SOME furniture in it
) if I was puttering around the house and could check to see if a "fun" major project was going on (like dissecting the sofa) from time to time, but not alone if I was out of the house. Of course, they usually wanted to be with me, and that was Okay if I was SURE I could watch them.
And somewhere between one year and two, after slowly increasing the space they were allowed in, they pretty much have the run of the house, at first only while I was in the house, and later, the whole place even when I was gone.
Your mileage will vary; some dogs are never
safe out on their own; some can only be left in one dog-proofed room. And two dogs left alone together can get into more mischief than one. That one is tricky, because some dogs aren't really safe together anyway...they're likely to start arguing over something which can escalate if you aren't there to deal with it.
And your personal preferences too, come into play in terms of what you want to allow. But like Bug said above, don't let them do anything as a puppy that you don't want them to do when they're an adult. Jumping on you, barking at you to get you to play, getting up on certain furniture or your bed, begging for food....whatever you think will bother you with an adult dog, don't let them do when they're puppies, even if it IS really cute.
It's up to you what you choose to be bothered by (though jumping on people is never a good idea) but if you decide to lay down a rule, be firm--don't let them get away with it even once, or it will be forever. Dogs typically don't generalize very well when you're teaching them commands (sit in the house is different from sit in the backyard is different from sit in the park) so you have to train them in each place. But for things like getting on furniture, all they need is once, and they've got it down.
Oh, and mine were always allowed on the bed. I like to snuggle with warm bodies, even if they have sharp edges and sometime sleep on top of you. It's easier to manage the night-time potty training trip. They get restless and start to move around and you can get them outside. With a really young puppy in a crate at night, sometimes you don't know whether yelping in the night is boredom or desperation.
But that's just me.