The F_ADSRx2 contains two ADSR modules.

Attack, Decay, Sustain and Release set the envelope, the way the sound behaves over time. A, D and R can be set between 10 ms and 20 seconds. The lower the A, D and R values are, the shorter the sound. Sustain is set from 0% to 100%. The sustain stage is reached after Decay. Sound will stay at the level of sustain until you release your key. You need to input a gate signal at the input and on the bottom the Envelope signal will be returned. Use the Envelope to drive a VCF to change sound, or to drive a VCA, to shape the volume.