To add your -2 Nursery students to a class go to Admin> Classes
If you do not see a -2 year visible to create a class, you will need to set up this as an academic year on your system. To do this go to; Admin> Config> Core Setup> Years
Here you can add the year group -2 by clicking "Add new" at the bottom of the page.
Then, go to; Admin> Classes
Here, create a class by selecting the nursery class, set and subject and click "Add new class."
You can then add students and teachers to class.
Click the "Add students to class" tab, select the year and then check which students you want to add to the class.