Consider the equation Cl2 + Mg----MgCl2?

A good way to remember the order of REDOX reactions is the word "OIL RIG". "Oxidation Is Loss" of electrons and "Reduction Is Gain" of electrons. So in this reaction Mg losses electrons therefore is oxidised and Cl2 gains electrons so is reduced. Also metals such as Mg are usually oxidised in reactions (they have a lot of loosely bound delocalised electrons) and highly electro-negative atoms like Cl and O are strong oxidising agents so they oxidise other atoms and become reduced in the process. Hope this helps and hasn't confused you more!