MODULATE ENV-AMOUNT

Anything that doesn't fit into other topics goes here!
Hi, I am a new user of LMMS. I am trying to figure out how to use the "modulate env-amount" under the EVN/LFO tab. I have read the documentation and still don't understand it. Could someone describe on how to use it?

Thanks in advance!
believe its a simple FM-modulation that follows the depicted graph. (You cant use it with VSTs btw.)