Origin
The grid of squares in the top left of the palette represents the sides and corners of the bounding box of the selection.
Click on one of the squares to select it (turns black). The X: Y: values will change to show the coordinates of that corner, side or centre of the bounding box.
Enter a new value into the X: or Y: boxes to change the currently active coordinate. The selected object(s) will move in relation to the change.