When drawing a line through a point parallel to a given line, we choose a point Q on line f and draw a line from f to X using a straightedge.
Next, we draw two arcs. The first arc (1.) we draw crosses QX and the line f. The second arc (2.) we draw with center X and using the same compass setting.
Next, we use the compass to measure the arc (1.) between A and B. Keeping that compass setting, we measure the same arc (2.) from C to point D which has been labeled below.
Finally, we draw a line through X and D. This line is parallel to f.