Steps to create student's version of jupyter notebook:

i. Create a project with the stack (Jupyter with nbgrader support stack) in your course.
ii. Add jupyter notebook file (ipynb file).
iii. Create .codio-jupyter file.
iv. Publish the assignment in the course.

The student file will be generated automatically by Codio when the assignment is published.
Check it out as a Test Student.

You need to create a .codio-jupyter file, the system will recognise this unit as jupyter with nbgrader, please check out jupyter with nbgrader document for more details.

Hope this will help you!

Note: If you get any error while publishing the unit, please validate the jupyter notebook from Education->Validate Jupyter menu in the IDE, you will get error logs which might help you find the issue it is having.