The software that comes with the labs is called Afinia Studio. You'll have to enter your information and choose the printer "H+1".
TinkerCAD is probably the best way to get kids started using 3D modeling.
When they have a grasp on how to create, let them explore Thingiverse. There are thousands and thousands of designs already created. It's fun to be able to take an existing design and modify it or just get some design ideas from others to see what's possible.
If you get some really advanced students, you can let them start modeling with expert 3D modeling software such as FreeCAD or Blender. These are the two most popular with FreeCAD being a more entry level option and Blender for those with a little more experience.