The boys narrating Ramayana before the huge crowd in Ayodhya are Luv and Kush – sons of Rama and Mata Sita. Sita lives in the ashram of Valmiki. She teaches them archery and other sciences. Valmiki teaches them Ramayana, the story of Sri Rama.
This story is later narrated by Luv and Kush in Ayodhya before a huge crowd.
This incident is found in the Bala Khanda of Valmiki Ramayana.