Plenty of resources

There are plenty of resources online to get started and learn GRASS GIS: from manual pages for each module and addon with examples, wiki pages with applications and use cases to beginner and advanced courses and workshops, videos and presentations for specific topics, jupyter notebooks with different workflows and books. There is also a Google Scholar profile that keeps track of scientific publications and applications of GRASS GIS in different domains. You may even try GRASS online to get a feeling of its capabilities!