See the official notification of classes aren't released by the University. Although if you have done the orientation program then you are registered as student of the university. So when the class will start they will obviously inform you on the registered contact numbers. Now apart from this you can contact the helpdesk of DOON UNIVERSITY they can also give you some information.

You can call the departmental heads as information offered by the official website:

https://www.doonuniversity.ac.in/index.php/contact_us

To know more about DOON UNIVERSITY visit the link below:

https://www.careers360.com/university/doon-university-dehradun

I hope this answer helps. All the very best for your future endeavors!