Mla module dual alt set up?

[Mha]

I bought a mla module to up my voltage in my truck. I got the dual alt pin to add an other alt. But no instructions on how to set it up. I emailed the guy but he said he sent the instructions and since wont reply to my emails. I have it hook up on one alt as of now. I know the other plug goes into the second alt righr . But theres a second wire that gets spiced but to what? Im guessing that that wire turnes on the second alt? Any help?