Is cars being stolen a normal occurence?

Hi, I'm new to Christchurch (NZ in general) and im planning to get a car. Ive heard and read stories of cars being bought and being stolen the next morning for those who parks outside their house. I havent experience or heard about stuff like this back in my home country so im just extra cautious.

Is it really normal? How can i prevent it from happening? How do ppl steal cars in the first place assuming its a modern car?