Do I have to schedule the same assessment window for all pupils?

No, when you schedule an assessment window, you are able to add and select particular applicants. Therefore, you can create multiple assessments with different applicants in each. 

Please make sure that you name your assessments clearly so that they are easily distinguishable and no confusion is caused. 

This may be useful if some applicants are sitting an exam in a different room and you need to download test codes en masse. You can then have two assessment windows, one for the main exam hall and one for the other room and download the test codes for each room.

Please bear in mind though that every assessment window should finish before the applicant’s earliest senior school deadline.