When my newborn is back for first few days everything is well sleeping in the baby cot. After that, she got a habit of ppl carrying and sleeping downstairs instead. How do I ensure the routine is back to sleeping in the baby cot? Please advise I don't wish to make it a habit that she will she sleeping downstairs at the sofa every now and then with people carrying her in the arms.

Establishing a clear bedtime routine may help when your baby's sleeping schedule (usually around 3-4 months old) become more predictable. What my friends did was to have a night feed 30-40 mins before bedtime. Following by a bedtime routine of simple wipedown, brushing of teeth/gum, changing into pajamas, bedtime story/lullaby or a "chat" (more like monologue) with baby, patting baby to change the association from being carried to these actions. For naps, they try to put baby back into cot once baby seemed drowsy enough, but not quite asleep yet. Sounds simple in theory but most took awhile to make these associations.