A NZ resident has the right to work for any employer, or study paying domestic rates (though not eligible for NZ student loans till they've been in the country as a resident two years), or start a business.
If you get Residence with some of your points coming from a job or job offer, it may be granted with a Section 49(1) condition AT FIRST, saying you must work in the job mentioned for three months. Once you show INZ you have done this, you get a second visa sticker without this condition on it.
Within NZ, the Resident visa is potentially everlasting. When it is issued, two years' travel conditions come with it, allowing unlimited going and returning to the country in that time. After the two years, the travel conditions run out, and
if you were outside the country, you wouldn't have permission to re-enter, so the residence would have lapsed. If you were still in NZ at that time, though, the residence would continue unchanged.
That previous page about PR tells you about all possible ways to qualify. Which you choose depends on your own situation. PR, which you can get after two years, once again gives the right to come and go freely, for ever this time.