Some browser have a strict autoplay policy. In Google Chrome and mobile iOS audio cannot be played unless the playback was initiated by a user gesture (click / tap). To free the audio context from the so called suspended state, a user interaction is needed which triggers the ResumeAudioContext op.
It has two modes – in the default one Show Overlay: true it will show an overlay over the cables canvas with a play button when the audio context is suspended.
When Show Overlay is set to false you have to manually take care of the user interaction (e.g. by adding a button yourself), registering a click / touch even listener and finally triggering Resume on this op.