Shairy
Welcome. You are doing a FYP now? I assume you are a polytechnic student then. you must have studied about ladder/structure logic/circuits. You been through a module where you learned how to do up simple circuits using relays, switches, timers..etc? If you had, you should know that a simple PLC program will work very much like a done up relay circuit.
Please read through the 'Learn PLCs' section in this very website, you will get a good idea what exactly a plc is. Please try to do some searching on your own, and ask when you are really in a fix.
regards
Sherine T.