I start feeding mine at about 4 weeks with quality dry puppy food crushed to a powder with a food processor, a little bit of quality puppy canned and warm water and make a soupy mixture, more licking than chewing right at first. I start adding less and less water as the weeks go by. My babies are almost 7 weeks now and they are still eating their food moistened 3 or 4 times a day, still nursing briefly about 3 times a day, and are able to eat the dry food which I leave out all the time now. I'm home all day and they keep spilling or playing in the water so I just offer drinks several times a day and remove the bowl. If you're not home with them I have heard people mention they do water bottles. Just make sure you clean them thoroughly every other day. Maybe it's not so critical with dogs, but I don't use water bottles with my birds because it is too easy to get lazy and then bacteria develops and you lose birds!
Here's is a good link on raising puppies - I started you on birth to 3 weeks, but if you scroll down, you will see links for Week 4, Week 5, etc.
http://dogbreedinfo.com/whelpingphotos3.htm