Hi Saad,
Most birds will not go into the box right away. It is best not to give them a box until they show signs of bonding as a breeding pair and mating. They only need a nest box during breeding season and after each clutch, you will remove it and lat the pair rest for a few months. The box should be affixed to the outside of the cage as high as possible. If they are ready to breed, they will start to investigate the box. If they show no interest, then it is best to remove the box until you see them mating. Do not even force a bird into the nest box. This can cause emotional trauma and might put them off the box entirely. Your most important role in breeding is patience – nothing happens overnight, it can take weeks, months or even years for a pair to settle down and breed.
Thank you for asking Lafeber,
Brenda