watch parent leave child.

on the second night after your tamagotchis got married set the time to 11:59. wait one minute and then the light will switch on. the parent will looking at the baby tamagotchi. then in a minute it will go up in the air and the baby will be alone. then the light will switch back off. then set the time back to normal and then you have to name the baby. then you start looking after it.