The input signal volume controls delay time and feedback amount of a delay effect.
The two Graphic Shapers allow for fine tuning the response curves, independently for time and feedback.
Switch the delay to “Beat” mode if you prefer to control delay time by beat divisions and change the Graphic Shaper Y grids to reflect that.

If you want to process live audio or use this as an AUv3 effect, connect the Amp (Input Gain) to the Audio Input module instead.