Some very good advice in all the above posts. I only thing I would say any different is to start her on the puppy food about 2 weeks before she whelps. I have brooders set up bc I raise pups outside. I use heat lamps in winter and fans in the summer. Puppies need to be kept around 100 degrees for the first 3 days. It's not like hatching eggs, it doesn't have to be exact. But make sure they don't get cold for those first 3 days. It's good if you can keep them in the dark as well. Don't worry about momma being able to see them. I promise you she knows exactly where they are. Also make sure you're whelping area is not too big. You don't want them to be scattered.
I also sprinkle milk replacer on top of her feed. Same kind I use for calves. Most of the time heeler pups will be eating puppy feed by the time they are 4 weeks old. Wet it to soften it and sprinkle some milk replaced on it as well. They figure it out quick.
Watch for coccidia. All pups, but especially my heelers are bad about eating crap, no matter how clean you try to keep it. If they look weak or failing and they have runny crap/diarrhea on their tails (also check to see if their butt is always wet, as a good momma dog will constantly lick it to keep it clean), get some Albon or Baycox, or take them to the vet. It's cheap and simple to remedy but left untreated it will kill them quickly.
Start worming them at two weeks, then 4, then 6, etc. not trying to throw too much at you. But these are just a few important tips.
One more thing. Some momma dogs are funny. Some are not. If everything looks to be ok I don't handle the pups at all for the first week or two unless it's necessary. Some don't mind. Some do.
Attaching a picture of a raised brooder I have. Not the best pic but it shows the inside of the box with the whelping rail, carpet in the floor, and the door to the outside run. I feed inside. Water bowl outside. I have flooring out of an old pig farrowing pen so I can wash it out easy. Concrete underneath brooder with a track on the back that's is piped to a lagoon. You don't need all this for a few litters of pups but it may give you an idea that helps you somewhere along the way.