Wikibase installations are – at this moment – best explored with the SPARQL query language. Specialists are able to write queries in SPARQL but this is not what you would do as a beginner. Most people take a look at an example of a query and then modify the example to suit heir needs.
Here just briefly for the beginning a couple of useful links.
Above: SPARQL in 11 minutes. Note: this video is not specifically on using the Wikibase software.
Above: Navino Evans, co-founder of Histropedia (http://www.histropedia.com/), demonstrating how to construct Wikidata Sparql Queries.
Useful First Aid Links
- en.wikipedia.org on SPARQL
- The Wikidata Query https://query.wikidata.org/ – click at Help to run exemplary queries.
- The Wikidata page with more information about the exemplary searches: https://www.wikidata.org/wiki/Wikidata:SPARQL_query_service/queries/examples
- Mark Longair: Why should you learn SPARQL? Wikidata! https://longair.net/blog/2017/11/29/sparql-wikidata/