Messages are automatically marked as previewed as they are viewed on the "Message" tab. Use the next, previous, first, and last arrows, to find any delete any messages that are not spam. By default, only previewed messages will generate spam complaints.
Optionally check government agencies (FTC, FDA, and SEC) as complaint recipients:

Place the mouse over each of the optional categories to see the following:
The spammer's subject is mis-leading so "FTC" is selected.
This message promotes a stock symbol so "SEC" is selected.
After messages are sent, the category check box will become disabled and remain checked. This is done to show that the agency was notified and to dis-allows re-sending.
Even if these categories are not used at all, each message will still send several Spam complaints to the sender's mail service provider.
Use this screen to send the complaints.

Leave "Send previewed messages only" checked unless you have already screen every message loaded into this program. If a non-Spam message is displayed under the "Message" tab, use the "Delete" button to remove it. It is probably best to block the message so it will not accidentally get loaded into Spam Complaint again. This has very little overhead.
There is usually a short delay when you start to send messages (a second). The program is doing some message analysis. If there is a longer delay, an error should display indicating that the mail host could not be found. If this happens, check your host name, port number, and credentials.
Stops sending messages. Later, start will pick-up where you left off.