Hi. Congratulations on your upcoming litter!
I have whelped 5 litters in the past couple of years (4 of our own and 1 with another breeder) and have really gotten a lot of hands-on experience in the whelping process as well as the problems you can run into (and there are a lot).
You need to have a whelping box for your expectant momma dog and her puppies. This should be large enough for the mother dog to lay down and stretch out comfortably and should also be large enough to accomodate her with her puppies in there. You will want to line this "box" with newspapers, towels and/or sheets - which you will have to change throughout her delivery and after the pups have all been delivered.
You will want to start taking her temperature every day once she is about 8 weeks into her pregnancy. You should check her temperature 2-3 times per day. Her normal temperature range should be between 100.5 - 101.5 or so. About 24 hours before she gives birth her temperature will drop to below 100 degrees - most likely into the 98 degree range. When it drops down, she will go into labor within 24 hours, so someone should stay with her at all times at that point. (You will also notice that her bottom will look swollen and soft/saggy-appearing. Her nipples will turn rosey pink and if squeezed, may excreet some colostrum.)
You should have a delivery kit on hand. This is something you can put together yourself and you want to have this ready ahead of time. Many dogs go through delivery without any problems and without needing any kind of assistance, but you should be prepared, because even experienced mother dogs can run into problems sometimes.
Your "delivery kit" should include: clean (sterilized) scissors (for cutting umbilical cords if momma is unable or unsure how to chew them), dental floss or string (for tying off umbilical cords), plenty of clean towels, alcohol or peroxide (to dip the ends of the cut umbilical cord in to help clean them), bulb syringe (for clearing out any fluid or mucous in the puppies nose and mouth), pen & notepad (you need to keep track of what time she delivers her 1st puppy and take notes - make sure that she passes the placenta, if she doesn't pass it right away, that's okay, but by keeping track on your notepad, you can be sure that she passes the same number of placentas as she does puppies).
If your dog does not pass all of her placentas, you will want to take her into your veterinarian to get a shot of Pitocin which will help her body to expel any retained placentas (these can cause a serious infection in the mother dog if they do not all pass).
The room where her whelping box is located should be warm, quiet and comfortable. Newborn puppies cannot maintain their own body heat for the 1st couple of weeks, so they need to be kept where they will be warm at all times.
Momma dog will need plenty of food, water and rest after giving birth to her babies. The day she goes into labor, she may refuse food - that is okay, she's just preparing to give birth. The day she has the puppies and even the following day or two her appetite may be decreased, that is also okay - just make sure that she does have plenty of food and water available to her at all times.
I would recommend that you do a search on the internet also to find websites by different breeders. There is a lot of useful information available.
You should also know what warning signs to look for in case your dog has any problems delivering her puppies. If she is pushing and pushing (hard labor) and not producing any pups after an hour or so - it's time to call the vet.
There are many ways she can have her puppy that are all within the normal range. Some pups can be born breech (tail/butt end first). Some may come out with the sac already opened. Some may have torn the umbilical cord before they came out. (For the ones with the torn umbilical cord, you need to get it tied off about 1 inch from the belly of the puppy - tie it in a double-knot, then trim off any excess umbilical cord and dip the end of it (that is still attached to puppy) in some alcohol or peroxide to sterilize it.)
If a pup has any difficulty breathing you can: A) wrap the puppy in a warm towel and vigorously rub the puppy to stimulate it to breathe. B) use the bulb syringe to suction out the puppies airway (remember to do this to both the nose and the mouth). C) If the pup still isn't breathing or you hear a lot of fluid sounds in their breathing - hold puppy upright with your hands firmly clasping the puppy in front and in back of pup - support its head. Hold puppy at your shoulder level with your arms bent upward, then move your arms in a downward sweeping motion so that puppy is now head-down. That will help to dislodge any fluid in their lungs.
I hope all of this information is useful. I didn't mean any of it to scare you. There really is a lot to know. Most people think that it is natural and easy - and usually it is. But to be a responsible breeder, you also have to be prepared for any possible problems or emergencies.
And above all, if your momma dog is showing you any signs of distress, do NOT wait to get her to the veterinarian....better safe than sorry, for momma dog and her puppies.