In the Size & Position menu you can set the width, the height and the placement of your element.
You can set the width and the height of your element to: – 1/1 (total) -1/2 (half) -1/4(quarter) of the content’s width or height.
You can also position your element horizontally and vertically, very easily with the three options given.
In the Other Size And Position Menu you can set the size and the position of your element by pixels.
You can also rotate your element by degrees here.
Watch a video about the properties: