Newborn screening involves a head-to-toe physical examination of a newborn to check for any abnormalities, as well as biochemical screening tests and special screenings to check for conditions like retinopathy of prematurity, hearing issues, and heart defects. The physical exam includes measurements, assessment of vital signs, and examination of features from head to toe to check growth and development. Biochemical screening checks for inborn errors of metabolism, while special screenings aim to identify conditions that require early intervention.