You can change the number of entries that is shown in a widget by following these simple steps:
Click on the desired dashboard from the My Sourcing Boards home page.
Go to the Widget Details tab. When you hover over the upper-right section of the widget, a three dots menu will appear. Select "Edit" after clicking on that.
Once you're in the "Edit Widget" window, update the necessary entry value and save the changes by clicking the "Save" button.