Click the Arrange | Move | Backward command or press CTRL+PAGE DOWN to move the selected object backward one level on the layer. You can also move objects forward or backward in the Object Manager.
In the left drawing, the red square is located in front of all the other objects. Click Move Backward to move the square back one layer so that it appears between the circle and the triangle (middle drawing). Clicking Move Backward again places the square behind all of the other objects (right drawing). Move to Back also places the square behind the other objects.
Move to Front
Move to Back
Arrange Tab Commands