When you insert an instrument, the instrument's GUI editor window will open. You can also see this GUI by clicking on the instruments grey name button in the Song or Beat+Bassline Editor. When you click the name button, it will change to lightgray. This instrument is now the active instrument. The name button acts as a toggle for the GUI editor window. Instrument GUI's have five tabs: PLUGIN, ENV/LFO, FUNC, FX and MIDI. The PLUGIN tab changes with the type of instrument. All other tabs are standard for every instrument, however the ENV/LFO tab is only available on the kind of instruments that can use this feature. VeSTige, LB302 and ZynAddSubFX plugins do not present this tab. An in-depth explanation of how to use the features on the various tabs can be found in the Working with instruments section.