Bylaws are filed with your state and are a legal document. They are the rules of a corporation, established by the board of directors during the process of starting a corporation. Specifically, the bylaws direct the board of directors in their work to oversee the organization.
Policies and procedures are how the work of the organization is carried out. Although separate from bylaws, they should always be in agreement with them. For example, if your bylaws state that your board will meet monthly, and you decide (by policy) to take the summer off, you would be in violation of your own bylaws.
As a general rule, bylaws should be broad to allow flexibility, while policies and procedures are specific instructions on how to carry out that work in alignment with your bylaws.