The organizing document might be called the charter, the constitution, the articles of incorporation, or the articles of association. This document sets up the bare bones of what your organization is - things that are very unlikely to change. This might include: name, objectives, basic policies, dissolution clause, what comprises membership, who the officers are, very basic info about meetings, how amendments can be adopted. This should be very basic stuff that you probably can't imagine ever changing (although it's possible to do so).
The bylaws are the rules by which your organization operates. So, for example, the constitution might say this about meetings:
"The Executive Board shall transact official business of the organization at Executive Board meetings and at General Meetings as set."
While the Bylaws could go into a great deal more detail:
1. A general meeting of the organization will be held in by September 30th to approve the budget for the fiscal year.
2. Members present at a general meeting shall constitute a quorum.
3. A general meeting of the organization shall be held in May of each year for the purpose of reorganization for the coming year.
When I first started researching this about 3 years ago, the set was what I understood was the "right" way to go about it. Since then, I've discovered many PTO's have a composite document, generally just called the bylaws. When we were getting our 501(c)(3), the IRS quite firmly seemed to expect us to have an organizing document besides the bylaws (for us, our constitution), so I'm not sure how others with a combined document have gotten around that. Perhaps the IRS has gotten more lenient. I'd be interested in hearing from others about this.
I'll send you a copy of our constitution/bylaws.
Note - if anyone else wants a copy, please email me. I check this Forum from several different computers. I may not notice or be able to respond to a request embedded in this posting, but if you email me, I'll send you a copy.