All of this is clearly explained in the Śrīmad-Bhāgavatam, and the reader has ample opportunity to study this critically.
In the modern age Lord Śrī Caitanya Mahāprabhu preached the Śrīmad-Bhāgavatam by practical demonstration. It is easier to penetrate into the topics of the Śrīmad-Bhāgavatam through the medium of Śrī Caitanya's causeless mercy. Therefore a short sketch of His life and precepts is inserted herein to help the reader understand the real merit of Śrīmad-Bhāgavatam.
It is imperative that one learn the Śrīmad-Bhāgavatam from the person Bhāgavatam. The person Bhāgavatam is one whose very life is Śrīmad-Bhāgavatam in practice. Since Śrī Caitanya Mahāprabhu is the Absolute Personality of Godhead, He is both Bhagavān and Bhāgavatam in person and in sound.