The place where your questions to the Wikidata Query Service are answered. Question to Wikidata can be about pieces of knowledge in this world and their relationships. This can be used to use Wikidata as a knowledge base or generate lists for other Wikimedia projects, such as Wikipedia.
We also have documentation for advanced users that goes beyond the first steps. The Wikidata Query Service provides an SPARQL endpoint including a powerful Web-GUI. SPARQL (pronounced "sparkle") is an RDF query language, that is, a semantic query language for databases. With SPARQL you can extract any kind of data, with a query composed of logical combinations of triples.
A gentle introduction to the Wikidata Query Service
This introduction introduces you to the user interface of the Wikidata Query Service. You don't need to learn SPARQL to modify queries and display results. This gentle introduction is a good start if you want to start playing around.