I leave my curtain open in the day and off all light except a small light at night to let baby know the night and day different.
Poop once a day or once 2 days is fine.
If u see poop stain, you try to tell the baby mmmmm.... mmmm... mmmm..
Soon baby will know they have to try to poop.
Also sometime it can be also due to formula milk.
Eileen Lau