@Arjunan, if your question was: "How to calculate concentrations from EDX data?" the answer is: Let it be done by the EDX operator!
You may sit beside this person and learn step by step how to do this and how to avoid traps. A good manual and/or textbook is mandatory.
You'll need a good spectrum with all necessary information and software. The software will usually calculate both at-% and m-%, and maybe confidence intervals.