It doesn't get much simpler than that! You need to work out which of the 2 cables goes down to the switch, as stated above. After that it's easy!
You have the 'dining room light' //www.diynot.com/wiki/Electrics:Lighting-Circuit-layouts
You have the 'dining room light' //www.diynot.com/wiki/Electrics:Lighting-Circuit-layouts