Hi,
you design a report in the Designer by dragging an element from the top (text, line, ...) into the report area. Click on an element in the report to select it and change its properties on the left side.
How to pass data depends on your application. If you hava a python web application you can directly use the reportbro-lib and pass the data as a dict to the Report instance:
https://www.reportbro.com/docs/methods#reportbro-libIn case you want to get the report in javascript, Java or any other language you have to make a web request and pass the data (along report and outputFormat) as JSON encoded post parameter. You can see an example in the reportbro-designer:
https://github.com/jobsta/reportbro-designer/blob/master/src/ReportBro.js#L1288Alex