Edelbrock Var Jection info needed.

Need info to know if this is worth it.

I got two of them. One the circuit board is burned and the other looks ok. I just have the module though. Has anyone ever used one? Is there a diagram for how to rig it up?

So far i have not found much on the net. Mostly just links to ebay for crap already sold. I know it is supposed to prevent detonation and pinging. What I dont get is how the vacuum draw is working. I think I might be missing a few pieces and need some pics of one new in the box or maybe one installed.