Flag protocol defines the proper placement, handling and use of flags. Some countries have added certain protocols into their law system while others prefer to have "guidelines" without civil or criminal consequences attached.
General guidelines are accepted practically universally.
The flag of honor, which is the nation's flag in most cases, is flown on the center mast if possible. It is also correct to fly the flag on its own right. To an observer it would be on the far left. If more than three flags are used, the proper position is as far left from the point of view of an observer. An additional flag may be placed on the right side, but is not necessary.
When two poles are crossed, the position of honor is the flag that ends on the left side from the point of view of an observer (the pole will therefore end on the right).
In a semicircle, the position of honor is the center. If a full circle is used outside an entrance to an arena or stadium, the position of honor is directly over the entrance. If used to line the walls of the arena, the flag should be placed directly opposite the entrance.