When you open a dashboard, it automatically retrieves data from the last two hours. However, you can modify the time range as needed. You can also configure the settings for the dashboard, then create a bookmark for that configuration.
Select Reports > Portal > Repository > Standard Content.
Expand the desired category, then select the dashboard that you want to view.
(Optional) To change the time range for the report, modify the start or end time parameters.
When you change the time range, the dashboard refreshes the data.