New Zealand passport holder traveling to Shenzhen for 4 nights

Part one:

Kaye, you are allowed to do this, but you should keep in mind that you will stay in Shenzhen for at least 24 hours and 1 minute. Shenzhen airport is not eligible for 24 hour visa free transit if your next destination are Hong Kong or Macau. You have to use 144 hour visa free transit instead and it means that your ferry from Shekou port (ZYK) has to depart at least 24 hours and 1 minute after your scheduled arrival by plane to Shenzhen airport! This is extremely important detail.

Also, to be eligible for this option, you will have to book your ferry ticket from Shekou to Hong Kong online in advance through CKS - Chu Kong Passenger Transport company website. You will receive an e-confirmation and you will print it out. Of course, you will have to take this printout with you as a proof of your transit. Also, you will use this printout to collect your real paper ticket at Shekou terminal. You have to know that you will have to take exactly that ferry you have bought your ticket for.

Part two:

I can see your dates and just one warning... You can arrive on 2019/12/04, but you are not allowed to stay in Shenzhen until 2019/12/11. You have to leave Shenzhen by 2019/12/10 with the last ferry. Also, you are allowed to travel throughout the entire Guangdong province when traveling on 144 hour visa free transit.

You have to bring your valid passport, your flight ticket and your ferry ticket. Also, you will declare in Seoul that you will travel to Hong Kong via Shenzhen using 144 hour visa free transit. It is highly advisable to bring a confirmation of your accommodation booking in Shenzhen for the first night because there are questions about your accommodation that you will have to answer in the blue form that you will have to fill out upon your landing in Shenzhen. This option does not have any fees, so you don't need money for that, but you will need some money for your usual expenses, including the metro, food or similar. Of course, you can rely on ATM to obtain a Chinese currency.