Teds_Studio
Maybe I was doing something wrong...but I couldn't get FDM to work. When I would drag the download link to the FDM icon....it would download just the link...but not the sonar file. I was doing this from within FireFox 24.0.
If it is installed correctly (i.e. FDM is configured to monitor FireFox), click the link in FireFox and FDM will intercept the download request and popup and dialog. Review the dialog, make changes if necessary, then press OK.
To check if FireFox is monitored by FDM, open the FDM main window,
Options > Setting > Downloads > Monitoring. Select the browsers to monitor. Monitoring will also add some options to the FireFox context menu (the one the pops up when right-clicking a link).
Edit: I use FireFox 24.0 and FDM