180 Degree Rule

Before filming my premliminary task i need to know some basic filming rules like the 180 degree rule. I learnt from this that say two characters in a scene should always have the same placing in a shot for example if two actors were facing eachother one on the left and one on the right then whenever moving the camera for a difernt angle on position the actors should remain in the same position as they were in before i.e the actor previously on the left should be on the left of the shot again and the same for the actor who was on the right.