Please refer to this guide for instructions on how to install the Metadata app, and how to make Metadata available for pages in a space or globally. Use the navigation on the left side to guide yourself through the chapters of the documentation.
The required permissions (Confluence Administrator, Space Administrator, ...) are indicated at the top of every page.
Metadata Permission Scheme (v 3.3)
Manage Global Metadata (v 3.3)
Installation and Licensing (v 3.3)
Manage Metadata in Spaces (v 3.3)
Export and Import Metadata Sets (v 3.3)