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To go into all that here would take too long esp. without pictures.
Basically F is a ratio of the lens opening to the focal length of the lens. Larger the number, the smaller the opening. The F2.8-4.7 means that when your zoom is in your widest position, the largest opening is 2.8...as you zoom in it changes (in stages) down to 4.7.
A wide lens shows a wide picture. A tele lens shows a close up. A zoom lens is adjustable between these two extremes.