A Module is an effect or visual source in modV, it draws something to the screen.
Use the Module Gallery to find Modules. The Module Gallery in the bottom half of the screen.
Drag a Module from the Module Gallery to a Group to create an active Module.
When selecting a Module, controls appear in the Module Properties panel, top right. These controls are specific to the selected Module and are adjustable.
To remove a Module from a Group, select it and press backspace.
To learn how to create a Module, see Writing A 2D Module.