Trip to Kolkata, need help!

Hello! A friend and I are visiting Kolkata for the first time from March 18th to 22nd. I don't know much about the city beyond the basics, so I need help planning our trip.

What are the must-visit places? Which cafes and restaurants should we try? Are there any hidden gems we should know about? Travel tips, please let me know if there's anything else I should be aware of. Thank you!