Why won't my Audi A1 start after a battery replacement?

I recently replaced the battery in my Audi A1, but now it won't start. The dashboard lights up and I can hear a clicking noise, but the engine won't turn over. What could be the issue here?

Check the battery terminals for corrosion, as this can cause difficulty in starting the car. Try cleaning the terminals with a wire brush and reconnecting them securely.

Make sure the new battery is fully charged before installing it. If the battery is not fully charged, it may not provide enough power to start the car.