Power BI Dashboards

I would like to create a dashboard for staff performance with drill downs using Power BI. I want to publish some of the dashboards to our staff intranet site and I want them to update automatically when I save new excel sheets to a specified file path. The underlying data will need to have calculated columns added and will be derived from a number of excel data sources.



I also want to understand how these are created so that I can do something similar in the future so the job will include some training time for me.