What do I need to convert mass of product to ma's of a reactant

Given A + 3B C+4D

For instant u have rhe mole of one of the compond of the given equation ...

Use the mole ratio of the balance equation and then convert to mass

Mole = mass : Mr

For instant mole ration of the productd to the reactant A is 4:1 ...

If u have mole of D u can find that of A and so on ...