Hello, Can somone help me understand how to do thid question

The combustion of paraffin (used in candles) is given by the reaction: C21 Hag(s) + 32 O2(g) 21 CO2(g) + 22 H2O(g) This reaction is strongly exothermic (AH--13,107 kJ/mol)! Using this enthalpy of reaction and the data for the standard enthalpy of formation (AH) for CO2(g) and H2O(g), calculate the standard enthalpy of formation (AH) for paraffin