EBF before milk comes in

I want to get some advice from experienced ladies about EBF.

When I had #1, 6 years ago, we stayed in the hospital for 2 nights. He was kept in the nursery most of the time. They'd bring him to me or I would go to the nursery during the day for feedings but I thought there wasn't anything coming out but would do it kind of for practice. He was getting formula in the nursery as well especially at night. I knew some of the babies in the nursery had a no formula sign but I (mistakenly) assumed their moms had milk from the start (I knew that some women's breasts got larger and leaked during pregnancy. Mine didn't change in size and had only leaked once or twice, so I thought maybe I had less, I know now that's not true)

Anyway, first day we're home. I breastfed him all day. When it was night time. He was nursing for a long time and then was getting frustrated and would cry. We tried a couple of things burping him, changing him, rocking him, we'd put him on the breast again and he'd latch and suck a little but then get frustrated again. My mom said she thinks he's still hungry so I decided to use some of the formula that we got from the hospital. Once we gave him the bottle, he drank most of it and fell asleep. That was the last time he had formula in his life.

The following day, my milk came in and he only had breast milk until he self weaned at 15 months.

Now, 6 years later, I am more educated about breastfeeding. I know babies like to suck for comfort and I know their small bellys don't need much. The hospital where I'm having #2 encourage that the baby rooms-in with the mother mainly to establish a healthy breastfeeding relationship and I am ready for that but how can I guarantee that baby would be full with what I'm producing the first few days. Is there anything that I can do so that I can avoid the need for using formula?