Transit visa

Carol, if you are traveling on a single ticket, your luggage will be tagged all the way to New Zealand or in other words, you will not have to do with it because it will be transferred by airport staff from one to the other flight.

Now, very important detail. You have mentioned that you have 90 day visa, it is important to keep it intact because it would be a shame to use it just for a short time that you will stay outside the airport. So, when you land in Beijing, you will first approach 24/144 hour visa free transit counter where you will apply for a temporary entry permit in order to be allowed to exit the airport. This is a formality and you will just present your flight tickets and also, this is important, stress that you want to exit based on a temporary entry permit under 24 hour visa free transit and not under your visa. Please, do not forget about this detail both the transit counter and later at immigration. Just be focused and defend the integrity of your visa.

Beside the mentioned, you do not need to do anything and just one more detail... When you perform a check-in at the airport from where you will depart toward Beijing, you will just ask for your confirmation and peace of mind, if the luggage is tagged all the way to New Zealand. Have a nice journey.