The Question bank can be found in the upper menu of CooSpace, under 'Questions'. By clicking on 'Question bank', you can navigate to the main page of the Personal question bank.
Here you can find:
Personal question bank: questions and folders created by you, that you have right to modify and delete.
Question banks of scenes: question banks that are in scenes can be accessed here, but you cannot modify or delete them, even if you have authorization of doing so; you can only edit them in the scene they are stored.