We know that migrants have a better experience and settle better when they have family already in the country. You will get extra points if any close family of yours are residents or citizens of New Zealand, and are living here when you apply and settle.
You will have to provide birth certificates that show your relationship with the family member. Your relation must not hold a current residence permit that is subject to Section 18A requirements.
Having close family in New Zealand will get you another 10 points on your EOI.