LowePro, I am in the beginning stages of learning to read these screens too. How deep did you catch the fish in the water column? From what I understand, those should be half way up in the water column??
Fish were staged from 12-16 fow, and I spider rigged with hooks at 9-10 feet down. Once I located the fish I post up on them with my 2D sonar so I could see the schools "true depth" in the water column.