VSTs are self-contained programs that 'plug-in' to FL Studio giving you access to a, virtually unlimited, source of new instruments and effects. FL Studio categorizes VST instruments as ' Generators' because some also generate control or note data, rather than audio. VST plugins generally come in two types, instruments (VSTi) that are designed to make sound and effects (VST) that are designed to process sound, although some can do both. VST is in addition to the FL Studio 'native' plugin format. VST is a software interface standard that allows you to load VST software synthesizer and effect 'plugins' in FL Studio. Watch tutorial videos here Plugin Types Supported Virtual Studio Technology (VST) Plugins