Most companies have three layers of documents: policies that say what must happen, safe work practices that describe how it is done in general and operating procedures that describe a specific task on specific equipment. In practice these layers are usually written and stored separately, so a change at the top does not reliably reach the bottom.
Linking them means each procedure step can point to the safe work practice it follows and the policy behind it. When a policy changes, the affected practices and procedures can be found right away, and an operator looking at a step can see why it is done that way if they need to.