1.  It is prohibited to use the light from the Chanukah candles.  Therefore, a separate candle, called the shamash, is lit.  The shamash is used to light the other candles.  The Shamash must be separated from the other candles, either by placing it a little bit away from the other candles, or by placing it a little bit higher than the other candles.  This is so one can see how many Chanukah candles were lit that night.

 

2.   The candles (or oil) must burn for at least 1/2 hour after the stars appear.  This rule applies whenever the candles were lit.  If one lights with oil, he must make sure he has enough oil to burn a minimum of 1/2 hour when he lights his flames.  One may not add oil after the flames have been lit.