How do you know?

I was just wondering how do you know if baby is getting milk from breast when breastfeeding? I know it’s a dumb question but I’m going to be a FTM and I keep thinking ‘what if I try to breastfeed & my baby just keeps sucking but no milk is coming out’ like how are you suppose to know? Do you feel the milk come out? I tried to google before I posted this but the only thing that came up was ‘how to know if your baby is getting ENOUGH breast milk’ which is not what I’m asking at all!