Each panel has its own schedule. The header gives the panel name, voltage, bus rating and main breaker or lugs. Each row is a circuit.
Example: an electrician reads a panel schedule to count breakers by size. One row shows a circuit for the gym backstop motors.
Use panel schedules to price the gear and to check the plans. Circuit numbers on the floor plans should match the schedule rows. Specialty trades can use them too. A circuit for your equipment in the schedule suggests the electrician carries the power.