The good news is that before you go to an immigration agency, you can do everything yourself.
All the necessary conditions, all the documents that you have to put in the file (including the forms that can be downloaded in electronic format), and all the procedures to be followed are clearly described in the official websites of the institutions dealing with emigration.
Please read the following pages carefully:
NZIS (New Zealand)
If you’re still unsure, check to see if your problems have already been answered in the Forum , or ask a new question – there are people who have been through this and can help.
Good luck to all,