I d suggest you read a bit before asking people to spoon feed you with information you should know if you want to mine.
Mining and not understanding the concept of difficulty is like wanting to drive a car and understanding what does your engine do.
I've worked in 4 different industries, and consulted on many different sites/projects, with god knows how many different variables. I am no stranger to being over your head, and not being prepared (you actually never can prepare enough for most situations). If there's one thing I've learned, it's jump in, take your lumps, you will emerge an expert on the way out.