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Start from your Home page (and make sure you're in the relevant Activity view to see the particular instance that you want to manage).
Locate the tile relating to the instance.
On the tile, press the 'Options' button (the one to the right of the 'Open' button) to go to the Options page.
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On the Options page, click either the ‘Shelve’ or ‘Unshelve’ buttons depending on your need.