How does The Manual apply in work situations (employer/employee)?

I understand The Manual when it comes to having one for a friend or spouse but what about having one for someone who works for you or someone you work for? For example, as an employee, there is literally a manual of expectations, and a contract of what you are expected to do in exchange for salary/benefits/etc.

As an employee, there are also expectations of the employer that, ie. given supplies to carry out tasks assigned that are less spelled out. When an employer or employee is not meeting expectations that are lined out, or have changed the expectations from the original contract, does this just become the circumstance? I understand how to make models on the situation but am trying to think of it in terms of the manual (this was brought up in my coaching session that I have a manual for my employer in terms of being given the instruments I need to do the job I’m asked to do) and if it’s actually helpful to not have a manual is this situation. Thanks in advance.