Size and position can be edited in two ways:
1. The size can be change by holding left click on the handles [1] of and element and draging them in the direction you wish. And the position can be changed with "Drag and drop", wich means you can hold left click [2] on an element and move it where you want.
2. Go to Edit [1] ribbon and click on Size and Position [2], make sure you have the element to be edited selected. Here you have a better way to edit size and position: "X:" [3] is the vertical coordonate and "Y:" [4] is the horizontal coordonate , "W:" [5] is the width of the element and "H:" [6] is the hight of the element. You also have arrows [7] for better precision in moving your elements.