In order to always have your questions organized in the Question bank, you can create subfolders for them. 

To create a new subfolder, enter the Question bank, and click on 'New subfolder'. This way a new row on the top of the list of existing folders will appear and you can name the subfolder. 

Click on OK, and the subfolder will be automatically created and you will see the page of the new subfolder. 

Here you can add new questions, create further subfolders, insert, import od export questions.