Hi Johan,
supporting documentation for charts can be found here: https://docs.mendix.com/refguide/chart-widgets
As you want to connect with external sources, real live representation and thus a more complex application I do advise you to take the Rapid developer course and exam; https://academy.mendix.com/link/paths/31/Become-a-Rapid-Developer
I recommend looking at the following documentation links:
https://docs.mendix.com/refguide/charts-configuration
https://docs.mendix.com/refguide/chart-widgets
To answer your second question (at least from the chart side), there is a refresh interval setting in the configuration of the chart