How do I turn off the alarm on my 2000 VW beetle

Im not sure why mine does it, but sometimes when mine does that, I have to open the trunk first and then quickly start the car and then the alarm is fine for a long time.

Thank you, Paul. I opened the trunk and started the car and the alarm di d not sound. I was wondering if I would have to do this every time I started the car. According to your answer I will not have to and that's a good thing. Thanks for helping, I appreciate it.

There is a reset button on the key device, press it to reset alarm.