ratha-yātrā-dine - on the day of the car festival; prabhu - Śrī Caitanya Mahāprabhu; kīrtana ārambhilā - began the congregational chanting; pūrva-vat - as previously; sāta sampradāya - in seven groups; pṛthak karilā - He divided.

On the day of the car festival, Śrī Caitanya Mahāprabhu began the congregational chanting. As He had done previously, He divided all the devotees into seven groups.