This guide presents the task mapping model (TMM), a snythesis/analysis methodology for aiding the interface specialist in designing interfaces with better usability. Briefly, TMM describes necessary knowledge for user task completion, and analyzes if this knowledge is supported by the user or interface. This framework consists of various abstract levels of task decomposition and description. TMM focuses on the mappings users make among domains (during task performance) to provide designers with specific information about task structure and user knowledge requirements. This model allows descriptions of tasks using hierarchical decomposition coupled with abstraction of user knowledge requirements.