Question:   How did the did the volume- temperature data obtained by Charles lead to the concept of absolute zero?

Answer:

Charles saw a linear relationship between the volume and temperature of a gas.  Extrapolating backwards, he found that the point where a gas would have no volume would be -273 degrees Celsius.  Since that's as cold as he thought things could ever get, that originated the idea of absolute zero.

As it turns out, 0 K is the lowest temperature that can be achieved, but not because of Charles law.  It actually has to do with the fact that at absolute zero, molecules have the smallest amount of energy possible, and have ceased moving back and forth entirely.  It's sometimes thought that molecules don't move at all at absolute zero - but there's still some vibrational motion in bonds even at this temp.