Making a graph on blood glucose levels?

how do you make a graph on blood glucose levels? first of all i have to convert mg/ml to mg/deciliter and then i have to put the concentration on the graph with absorbance on the y axis...and then how do i add a "best fit" line (regression line, i think) and i also have to add the equation y=mx +b...how do i get the values for this equation?