The Business Manager Analytics Reports are now the Historical Business Manager Reports. The reports are only available for viewing historical data. For your current business insights use the B2C Commerce Reports and Dashboards.
When: The Historical Reports are available in Business Manager with the B2C Commerce 21.5 release.
How: You can access the Legacy Reports in Business Manager > Merchant Tools > Analytics > Historical Business Manager Reports.
You can access the Reports and Dashboards in Business Manager > Merchant Tools > Analytics > Reports and Dashboards (New).