The first time you run the program, it will ask you to read and agree to the License agreement and also to a disclaimer on the use of the Phonogram digests. The program will not run if you don't agree to this. Once you signify your agreement, the disclaimers will still show as the program loads, but will disappear automatically after a few seconds. Once this is complete, the program will open. To import some digests, use the import button on the main toolbar.
Most functions are accessible by using the toolbars, or by clicking the right mouse button.
The few that aren't include Freeform Delete, where you can specify the criteria used to decide which messages to delete, Database functions, which can repair the database or compact it. Under normal circumstances, repairing the database will not be necessary. If you delete messages often, it's recommended that you periodically compact the database. This will minimize the amount of space taken up by the database file. And as a side benefit, it also creates a backup of your database.