Assuming you would like a step-by-step guide on how to open the petrol cap on a Toyota Aygo:
1. Locate the petrol cap on your vehicle. It is typically located on the right side of the car, near the back.
2. There will be a small lever or button near the petrol cap. Press or pull this lever/button in order to release the cap.
3. The petrol cap will now be released and you can lift it up to open it. Be careful not to lose the small lever/button, as you will need this to close the petrol cap after refueling your car.