This manual is intended to provide guidance for evaluators in applying the Index of Electronic Equipment Operability. In addition to this manual, application of the Index requires a Data Store booklet and an Evaluation Booklet. The Data Store provides quantitative standards for estimating human reliability and speed of performance for various types of operations. The Evaluation Booklet contains a standard format for recording the results of an evaluation. Background information concerning the Index and a description of its development are presented in the technical report, Development of an Index of Electronic Equipment Operability. This instruction manual is divided into three major sections. The first section provides a general description of the Index and its purpose. The second section contains detailed instructions for applying the Index. Explicit instructions are provided for the data collection, scoring, and summarizing steps in the evaluation. General guidance is offered for the judgmental processes of interpreting the results of the evaluation and deriving design and other recommendations. The third and final section of the manual is the Appendix, which contains samples of the various forms used in the application of the Index.