If your not going to breastfeed you'll have to start pumping immediately after birth (i know some people have even started earlier, to help start labour). In the beginning you will get colustrom, it doesn't look like much but its perfect for your newborn and there tummies are so small it doesn't take much to fill them!
I started off pumping for my LO, it is a lot of work, but it is definitely possible!
Good luck! It is exhausting in the beginning, just like breastfeeding, because you will be pumping constantly. So don't get discouraged! You can do it!
Have you decided what type of pump you will use? If you can afford it, I would highly recommend renting a hospital grade double electric pump. It makes the whole process much easier!