As a father of 7, I agree. You have to train your children how and when to sleep or someone is going to be up once or twice every night for years to come.
Training starts right away but it takes a while to reach the point they're sleeping through the night as defined as '8 hours of uninterrupted sleep three nights in a row'. A wake-sleep-eat cycle will help your infant get there by 12 weeks. This book will save the sanity of new parents - recommended. "On Becoming Baby Wise: Giving Your Infant the Gift of Nighttime Sleep"