The  Level 2 Assessment Plan  will help you plan your assessment programme for the year.  It has all dates for all subjects.  The subject specific documents give you more detail.  Make sure you have recorded the dates for your subject assessment in your diary.  

There will be times when you have lots of assessment bunched up together.  You need to know when these are coming up and plan your homework time carefully.
You can access the NCEA exam timetable for 2018 here.