The sleep of babies and toddlers and young children is qualitatively different from adult sleep. They have shorter sleep cycles, they spend more time in lighter sleep, and they have a more historical sleep rhythm thus are inclined towards biphasic sleep.

These things add together to mean that our younger ones wake more frequently and after shorter periods and may even have longer awake periods during the night. Completely, 100% normal.

You cannot and do not need to ‘teach’ or ‘train’ your child anything to do with sleep, just provide them with the right environment and let biology do the rest.