The Volume dialog will pop up if you select the Volume...item from the Register menu.
You can see the volume list box in the upper part of the dialog, which shows all the volumes of the current database.
Below the volume list box, you will find the Used progress bar. If you select a volume in the list box and click the Check button just right to the bar, the bar will show the percentage of the volume already used. The percentage is obtained by dividing the current directory usage by the value specified in the Volume Capacity(MB) field in the Preferences dialog.
In the lower part of the dialog, there are various buttons, whose functions will be explained in the following sections.