During install of the extension you can configure where the Indexing module might appear in the backend.

Nevertheless, like other modules you have to grant access to the Media>Indexing or Media>File>Indexing module. This can be done in the backend users record or the records of the usergroup he is a member of.

To get additional meta data out of files the DAM needs services of the types metaExtract, textExtract and textLang installed. You can check if those services are installed if you select 'Info' in the modules main menu.