Creating a query definition is a requirement for the component to function correctly, and you must provide a hierarchical structure for the results set.
As an example, open the PivotTree_Sample_esm.bqy, and from Sections, select Sales PT Results. The Item Type column represents the first level of the hierarchy, Store Type is the second level, OS is the third level, and State is the fourth level. The columns called Units and Amount are summary data. Therefore, to define the query, you must decide on the hierarchy and facts that are required before building the query.