This tutorial focuses on introducing participants to Annif, a multilingual automated subject indexing tool that can enhance for example a library's metadata generation system. Better metadata contributes to easier discoverability, emphasizing Annif’s – and this tutorial’s – impact on information accessibility and retrieval as well. Through hands-on exercises and demos, attendees gain practical experience in setting up Annif, training algorithms with sample data, and utilizing the tool to generate subject suggestions for new documents. The tutorial covers basic and advanced usage scenarios and allows participants to deepen their understanding and proficiency in implementing Annif for efficient metadata production in library systems. We will also demonstrate the use of Annif in institutional repositories. The tutorial is aimed at anyone with an interest in library automation including developers, repository managers and metadata librarians.