Hint on Balancing Equations
A balanced, stoichiometric equation must have an equal number of atoms of each element on each side of the equation. This is done by placing stoichiometric coefficients in front of each reactant and product such that the atoms all balance.
When balancing a chemical equation, you never want to start with an element that appears more than once on either side of the equation. In the equation above, oxygen is in both of the product molecules on the right side of the equation, so you should not try to balance the oxygen atoms until both the iron and sulphur atoms have been balanced.