This work describes how to use software which can process a set of goals to be achieved, alternatives available for achieving them, and relations between goals and alternatives in order to arrive at or explain the best alternative, combination, allocation, or predictive decision-rule. The software is spreadsheet-based, with goals on the columns, alternatives on the rows, relations in the cells, overall totals for each alternative at the far right, and the capability of determining what it would take to bring a second-place or other-place alternative up to first place. The book presupposes no prior knowledge of computers, software or decision analysis. It begins at an introductory level, describing data input, tentative analysis, and what-if analysis. It applies to either accessing existing files or creating new files. The book then proceeds to an intermediate and then to an advanced level where the software is concerned with prediction, explanation and causal analysis.