The color of the wires is the same as the Terminal Data Types that's on the quick reference card. Clusters such as the error control are a mix of data types and are represented by the thick pinkish, sort of dashed wire. Clusters of numeric data type are brown and dashed. Arrays are thicker and of the same color and style as the base element. To become familiar, you can create some controls and indicators on the front panel and just wire between them.