How do you construct a parallel line?

You place a ruler on a piece of paper and trace both sides. Put the point of your pair of compasses on the line and draw a circle. Then draw another circle, that is the same size, the same way further along the line. You will then be able to use your rule to draw a line that is a tangent to the two circle, and so parallel to your first line. Once you have done this you will realize that you don't need to draw a full circle just a small arc.