Making map use set of coordinates in QGIS

I have made a custom google map with the google map api which has a few functions that work well within it – one specifically is limiting the user on what they can view within the bounds of the map.

The map is a very simple 2 sides the front and back of the human body.

What I want to do is add on specific zones in my body, I’ve read that I can do with via geojason and have been pointed towards qgis to generate my GeoJSON data.

Now with is where I fall down I can make the zones and even the export just the coordinates don’t match up. How do I make the coordinates match?

I know to use EPSG:4269, but the coordinates still don’t match.

How do I make it match i.e. set a specific long/lat that my map is using?