Which distro are you using?
As @tenkian said it installs a systemd service, so it should be a matter of running:
systemctl start duplicati
If you want the tray-icon, change the launcher executable to use:
duplicati --no-hosted-server --serverurl=http://localhost:8200
That will make the tray-icon start on login and point to the already running service.
If you cannot (or will not) use the systemd script, you can simply run
mono Duplicati.Server.exe &
In an init.rc script or similar.
The email setup is explained in this topic: