When you use a live connection, during connecting to the data source, you would see an option of Automatically Update button on the screen.
Updates are provided for database sources or any online connection sources, so you can refresh the data every time you use the data by updating Now.
If you click on Automatically Update the whenever the data is accessed, the source is automatically updated. You aslo have an option of refershing the data whenever required.
Dashboard and the sheets would change automatically whenever the data is refreshed either automatically or by user refresh.
Hope it helps!.