The (district) Student Code of Conduct will be adhered to at all times by members of our organization. Any violations of the code of conduct will be immediately referred to administration for appropriate disciplinary action, and if necessary, may result in suspension or removal from the program.

The end.

As for late/time, etc, set the standard and enforce the consequences. You don't need to codify everything, or the very first time you don't follow your written policy, you've invalidated it.