If you want to understand Srimad-Bhagavatam, then you go and study Srimad-Bhagavatam from the pure devotee. Then you’ll understand.
You study Srimad-Bhagavatam from living bhagavata. So if one does not take or does not surrender unto the living bhagavata, he cannot understand Srimad-Bhagavatam.
From Srila Prabhupada’s lecture on Srimad-Bhagavatam 2.3.23 — June 20, 1972, Los Angeles