Rule is the guide line or law that drives processes and procedures for example laws of road like speed limit,Maximum speed etc.
Policies are the guidelines under which Procedures are developed.Policies address what the Policy is and its classification, who is responsible for the execution and enforcement of the Policy, and why the Policy is required.
Procedures define the specific instructions necessary to perform a task or part of a Process. Procedures can take the form of a work instruction.How to start and to take the task to completion.