The coordinate system in FreeSewing — and in SVG — follows the same rules as text on a page. You start at the top-left, and as you go to the right, the X-coordinate will increase. As you go down the Y-coordinate will increase.
The image above illustrates both the X-axis and Y-axis.
On the X-axis,
20 is further to the right than
On the Y-axis,
50 is lower than
The Y-axis is inverted in many drawing programs, with the origin
(0,0) being the lower left corner, rather than the upper left corner.
This is a common point of confusion so keep in mind that the Y-axis may not behave as you would have intuitively expected.