It is very simple just buy tow clay pots one big one small join them together with 4 inch bolt and washer, and on some kind of stand ,, use bricks if you like.. to put pots on upside down and light candle beneath it !
http://tune.pk/video/1796691/CandlePoweredSpaceHeater-DIYAirHeater190F-TableTopSize-EASYInstructions
http://tune.pk/video/1796691/CandlePoweredSpaceHeater-DIYAirHeater190F-TableTopSize-EASYInstructions