1st - never a dumb question. Ask everything you want for the information you need. The limb nock is the grove in the bows limbs where the string goes.

The bows shelf is where the arrow sits and the strike plate is the side of the bow where the arrow butts up against. The back of the bow is what faces away from you when drawing. The belly is the side that faces you. Just some added terminology to help.

you will be shooting 47#'s ata 28" draw length. If you draw 27" then subtract 2#'s = 45# If you draw 29" then add 3#'s = 50. Two pounds for every inch under 28 and 3 pounds for every inch over 28. Either way a 14 or 16 strand flemish sting will do.