Perfect! Have a nice trip with the bernina express.

Don't forget to add the trip in the pass (app) or write it the paper pass.

I don’t understand the requirements hence asking. Yes, I have already purchased seat reservations. If that is all is required for global pass holder, then great. 
 

Thank you.

Hello.

If you have already purchased reservations for the Bernina Express, than you don't need to do it again? Or am I missing something here?

You train ticket is the Interrail or Eurail Global Pass. You need a reservation for the panoramic cars.