Ham radio clubs have bylaws to establish rules and standards that govern the club and ensure that it operates smoothly. Bylaws are like internal laws that help the club regulate itself.
The by-laws detail specific actions as guided by the constitution. As an example your constitution may authorize the club to collect dues from its members whereas the by-laws will specify the amount of the dues to be collected and when they will be paid.
Once a 'social' club reaches a certain size, it becomes vital to have bylaws. These are rules set by an organization so that it can regulate itself. They ensure that there are certain standards and practices that must be maintained regardless of who is in charge. Think of them as the internal laws of your club.
https://www.arrl.org/files/file/Clubs/Club%20Constitution.pdf
Download the SHARC Constitution (2013)