1. Make sure you have the key fob for your car.
2. Press the unlock button on the key fob. This should turn off the alarm.
3. If the alarm does not turn off, try pressing and holding the unlock button for a few seconds.
4. If the alarm still does not turn off, you can try using the key to unlock the door. This should also turn off the alarm.
5. Once the alarm is off, you can start the car as usual.
If you are still having trouble deactivating the car alarm, you may want to consult your car's owner's manual for more specific instructions.