I would like to know if i want to bring baby for jaundice check up, can I just walk into the polyclinic?

Yes. There is priority queue for newborn. There will usually be a polyclinic staff who stands beside the queue number machine. Let her know that you are coming for baby juandice check out and she will help you to get the priority queue. That is what I did last time. I just walk in with my baby. Alternatively, you can make appointment online. Remember to bring his health booklet, birth certificate and CDA account card.