I'm going to assume you know what a xy-coordinate plane is. If you don't, then please look here:
Graphing Equations and Inequalities - The coordinate plane - First Glance
To graph this line, pick any two arbitrary x-coodinates and find their corresponding y-coordinates. Then plot them in a coordinate plan and draw a line that contains these two points.
I suggest that you pick the x-intercept (the point at which the line crosses the x-axis. i.e. (x, 0) ) and the y-intercept (the point at which the line crosses the y-axis. i.e. (0, y) ). Plot these two points and draw a line that contains them. Make sure that you draw the arrows at each ends of the line.