The startup procedure for the Airbus A320 involves several critical steps to ensure the aircraft is prepared for flight. Here's an overview of the key procedures:

1. **Pre-Start Checks:**
   
   

   • Parking Brake: Set.

   • Chocks: Removed.

   • External Power (GPU): Connected.

   • Thrust Levers: Idle.

   • Engine Master Switches: Off.

   • Batteries: On.

   • Generator Switches: On.

   • External Power: On.

   • ADIRS (Air Data Inertial Reference System): Set to NAV.

   • Panel Displays: Brightness set.

   • Navigation Lights: On.

   • Landing Gear Lever: Down.

   • Flaps: Up.

   • Spoilers: Retracted.

   • Fuel Quantity: Check.

   • Seat Belt and No Smoking Signs: On.

2. **APU (Auxiliary Power Unit) Start:**
   
   

   • APU Master Switch: On.

   • APU Start: Engage.

   • APU Bleed: On (adjust temperature as required).

3. **Engine Start:**
   
   

   • Fuel Pumps: On.

   • Engine Mode Selector: Set to IGN/START.

   • Engine 2 Master Switch: On.

     • Monitor engine parameters:

       • N2 Increase: Confirm.

       • Fuel Flow: Check.

       • EGT (Exhaust Gas Temperature) and N1: Rising.

       • Oil Pressure: Rising.

   • Once Engine 2 is stabilized, repeat for Engine 1.

4. **After Start Checks:**
   
   

   • Engine Mode Selector: Normal.

   • APU Bleed: Off.

   • APU Master Switch: Off (if not required).

   • Ground Spoilers: Arm.

   • Rudder Trim: Neutral.

   • Flaps: Set to takeoff position.

   • Pitch Trim: Set.

   • Status Reminder: Check for any alerts.

   • Nose Wheel Steering Memo: Ensure it's not displayed.

These procedures are standard for the Airbus A320 and are essential for safe aircraft operation. For a comprehensive checklist, you can refer to the A320 Normal Procedures.

Note: Always consult the official Airbus Flight Crew Operating Manual (FCOM) or your airline's Standard Operating Procedures (SOP) for detailed and specific procedures.