Text Properties Dialog "Size & Position" Page
This page lets you change the size and position of your text object. This is probably easier to do outside the text properties dialog, simply by clicking on a text object's title bar and dragging it to move the object, or by dragging one of the text object's red resize bars to resize it.
However, if you're the punctilious sort, or you believe that the dimensions of all elements in your labels must be factors of the Fibonacci sequence, or of the lotto numbers that made you a millionaire, then this page will be just your pace. In that case, you can just type your favored location and width and height into the provided fields.
Lock Size and Position: Check this box if you've got your text object in the exact position and size you want and you don't want to accidentally move or resize it. Once you've locked a text object, you'll be unable to move or resize it until you unlock it again. Please note that if you've got this box checked, the other size/position controls on this dialog will be disabled.
Note: "distance from label top" and "distance from label left" refer to distance from the top and left of your label's bounding rectangle. So if you're editing the position of a text object on a CD label, which you have probably noticed is circular, the left and top distances measure from the spot you would get if you made an imaginary rectangle completely enclosing the label.