Format Tab

The Printing box is used to define the paper size of the current plane. If you define an A3 paper format for the current plane, with your drawing defined inside the paper limits. When printing, to an A4 size, the drawing will be scaled down.
Select the type of paper orientation: Horizontal (landscape) or Vertical (portrait).

Center-Allows to default to be set for the center of the page.

Here you will set the units in which you want to work in