The Fluidsynth extension adds convenience to working with the Fluidsynth sampler:

• The element Fluidsynth Sound supports Fluidsynth specific features.
• The Fluidsynth View can be used to modify fluidsynth's reverb and channel.
• The Fluidsynth Customizer allows convenient customization of all Fluidsynth settings in a disposition.

For Windows a Fluidsynth distribution is already included in the extension - there's nothing additional you have to do. On Linux you have to have the Fluidsynth package installed via your Package manager.