and btw angela the bridge shall be placed, so the distance from the nut to the 12th fret is the same as the distance from the 12th fret to the bridge. Said in another way, the 12th fret is under the middle of the swinging part of the string.
LC
It seems positively churlish to correct such a disingenuously charming post, but I do feel obliged to point out that the "saddle" (rather than "bridge") should be located a tad further from the twelfth fret than the distance from the nut to the twelfth fret.