switch to prusaslicer - cura sucks.

basically the origin is set in the slicer. But as i don't use cura can't help on where to put your settings.

I will say that on my i3 you set the origin to 0x0 and the slicer (in this case simplify3d) uses that and the bed size to start printing in the centre of the build plate.

On my other printers the origin is set to the centre of the bed itself. But i3's seem to work differently :-)