Your heading into the first waypoint of the plotted course decides the way the course unfolds.
Say the crossing point of an x and y axis is the first defined point of the pre-plotted course.
The cross defines four sectors or quadrants, counting 1 to 4 clockwise from upper left to lower left.
The course unfolds into the diagonal opposite sector.
If you come from quadrant 4 (south-west) the pre-plotted course will unfold upwards and to the right - into sector 2.
If you come from quadrant 1 (north-west) the course will unfold downwards and to the right.
If you want it to unfold upwards and to the left you have to come from sector 3 (south-east).
If still unclear I can draw a sketch.
