I have linked to the Global Media videos before. Such an amazing repository of videos for parents and healthcare workers across the world. We owe the families who agreed to take part in this project a debt of gratitude.
This one has some excellent information on proper attachment of the baby to the breast: https://globalhealthmedia.org/portfolio-items/breastfeeding-attachment/?portfolioCats=191%2C94%2C13%2C23%2C65