If the game allows you to absolutely position the mouse cursor to a set of coordinates, you can use the mouse move action to do so ("Mouse >", "Move").
You can use the "Set Coordinates" button to open a dialog that will display the current coordinates, and allows you to press a keyboard key (the default is F8) to record the current location, which you can then apply to the action by clicking "OK".
Some games don't use a mouse movement system that allows for this, in which case you could try working off a screen corner (as a "home" position) to use relative cursor movement, but that is rarely practical.