There are many types of data sources in the Dashboard, such as MongoDB, PostgreSQL, MySQL, Azure…etc. You can also use simple JSON to get data through API. You can see all the data sources that you can add to on your panel. Go to Configuration >Data Sources>Add data source.
Otherwise, for some specific applications, please implement your own data source plugin in Dashboard.
You can learn how to do it by taking WISE-PaaS core Level III training course.