After adding a new data source and a new report,
drag and drop a table from toolbox to the layout of the report.then select the table and right click, then click properties, then in the first(General) tab, choose the dataset name, then click on the groups tab, and then add a group, for each group, set the name and choose the expression and then visibility. normally the first group is visible, but the second level group visibility is hidden and can be toggled be another report item selected from the list.
Then from the dataset left panel, drag and drop the field for that group.
if your report needs a parameter, right-click on the layout and click Report parameters and then add a new parameter, you might need to create a new dataset for available values for that parameter.
then go to the Data tab, edit your dataset to include the parameter and filter.
then click on preview tab and see the report.