The Rules are Here.  Briefly, orienteering is about finding your way around a set course independently with the aid of a map and compass only.  Rule 26 is all about conduct.  The answers to the most commonly asked about rules:

• Navigation devices apart from your map and compass are not allowed to be used (however you may take a watch or phone with GPS functions provided you do not use these functions).
• No interfering with control equipment.
• No seeking assistance from other people out on your course except if you are injured and can not get back to the finish unaided.
• If you come across someone else who is injured you must help them if they need it.
• Be quiet so you don’t distract others (no striking up conversations).
• Be fair, honest, respectful and have a good sporting attitude.