Wiardgroup

i have been looking at the envelator for a while attempting to
understand it some more ....here is what i do not understand "The
module also contains a DC coupled voltage controlled crossfader which
forms the sustain control when patched as a classic ADSR" so...we have
a attack portion ....a decay portion ....then the attack of the second
 generator is panned into the sustain input ?  and then we have a
release ? can someone explain for me ?