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If there are any labels that needs to be changed on the ribbenribbon, they are in the bottom of the XML file, and can replaced at your leasureleisure.
Now that the XML file is ready, have the Office 365 administrator upload the file, following the documentation here: https://docs.microsoft.com/en-us/office/dev/add-ins/publish/centralized-deployment
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This is done by opening an Office program, e.g. Word, going to File → Account, and logging in there, with an account that is part of the organization organisation the plugin was distributed to.
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