This document provides guidance on using different words to express permissions, prohibitions, requirements, recommendations, and possibilities when providing instructions or rules. It notes that "you may" and "you are allowed to" express permission, while "you mustn't" and "it's forbidden/prohibited" denote prohibitions. "You must" and "it's necessary/essential" signify requirements, and "you should" means a recommendation, while "you shouldn't" advises against something. Finally, "you can" and "it's possible for you to" convey what is possible.