It's all thoroughly explained in numerous other threads, and there is such a wealth of info to get by just typing in the right words in a Google websearch or our Search Engine, that it's now time you start READING.
UTFSE, Google and a University library if possible.
And read the "How to - Use The Fuckin Search Engine - " sticky thread up there.
This goes for all you lazy newbees, earn your Membership of this community by proofing to us you'r cut from the right wood :
Inventive, self-supporting/supplying, thorough, dedicated, hardworking and selfstudying, but above all, NON-GREEDY at all times. LT/