VTA Direcrtions

Can anyone tell me how to adjust the VTA? I have a VPI Superscoutmaster with the Nodost wired arm, and a Benz Ebony high output cart. I know how to physically raise/lower the arm while its playing, but don't know what to listen for to find the correct VTA. The directions say to start with the arm exactly parrellel to the record, and then adjust. Adjust to what?? Thanks