vasamsi jirnani yatha vihaya
navani grhnati naro ‘parani tatha
sarirani vihaya jirnany
anyani samyati navani dehi
As per this verse from Bhagwat Gita whose ever took birth here has to meet his death n similarly even being the supreme god of the universe lord jagannatha and his siblings has to left their old bodies and acquired new one that what nabakalebara means.
here in this video it’s shown the puja of Maa Mangala at Kakatpur temple,Puri and there after they began their journey in search of the divine trees and selecting the holy tree of sri sudarshan first which shows some divine spots on it. and the puja and fire sacrifice at the spot and the cutting down of the holy neem tree.