Use the highlighted toolbar button highlighted below to show / or hide the panel which contains new note stacks. Here you can capture description of new Rules, Scenarios etc. and then drag the notes to the right.
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Always show new Story notes  This is can be useful when you need to split the current user story into further separate stories. You can temporarily capture the newly split story onto another User Story note card in the current Feature before creating a new Jira issue and moving it there under its own Feature panel. |
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Slide out from the right The new notes panel can be configured to slide out from the right rather than from the left using the menu option highlighted below  |