Click on Menu in the Navigation and you will see a drop down showing Categories, Items, Options.   

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Simply drag and drop a category to change the sort order.  Toggle Off if you want to remove a category from your Menu.  If you want to add it back then click in the Inactive Tab and just Toggle back On.

Simply click on the Category and then update the name and save your changes.

You can search for an item by name or you can filter by Category.  Toggle OFF to remove item from menu.  Or Click on the item you want to edit.

You can update the Name or Description or Price and then click Save when finished.