Have realistic expectations. A breastfed baby is nothing like a formula fed baby. Breast milk is so perfect for a baby that it digests so fast! As well as baby needing to increase your supply, so you will be feeding a LOT! And I mean a LOT! There is no such thing as 3/4 hour gaps between feedings for quite some time. (with the rare exception). Your baby will love being with you and on the breast, and may want to be with you all the time because the feel safe and secure with you. Please also remember that frequent feedings progress into night time too. So while some bf babies will sleep 3/4 hours a stretch, many will not, and many will need feeding every 2 hours or even less for the first few weeks. I stress this not to put you off, but because I meet SO many mums who've ff'd the first children and then think "Oh well I don't have enough milk", "He wasn't satisfied", "He wasn't sleeping" ect.
Remember ALL this is NORMAL newborn behaviour. Babies need to wake and feed this often, its biologically inbuilt in them. If a cave-baby slept 4 hours at a time right from birth, then liklihood is that it would be eaten by wolves the first week! They wake for food, to alert the parents that they are there, they wake for comfort, they wake because they are windy, or have soiled their nappy, or just for a cuddle. All these are valid reasons to wake. (I'm sure you know this from your first two, but understanding the wakenings will be more frequent is so helpful).
Apart from having realistic expectations, I would say get yourself to a BF group in your area now, before baby arrives. Its so much easier to call someone and ask them a question or ask for help or support if you've already met with them.
Know that pain is not okay! Breastfeeding will probably feel strange for a day or two but it should not feel painful. If it is painful please ask for help. Its usually only something minor to change and everything will be well again.
Also for every breastfeeding problem, there is a breastfeeding solution. If you have your heart set on BF make sure your HCPs and family are supportive of that decision and do not be bullied in FFing.
Good luck and if you need a us, were here!