You can move objects in Ready using the equivalent of layers. When you select an object during edit mode you will see forward and back arrows in the blue box surrounding the object. Tapping the arrows sends the object forward or back in the scene.
Separately, under appearance you will see a layer area- you can chose between user interface (always in front, won't scale with scene), scene, and background (behind the scene). Using the background layer you can put things as decoration that won't collide with anything in the scene.
During run-time you can move objects in their layers by using the event manager. WHEN [something happens] DO [object] / position / set depth index / [number].
I've attached two screen shots for you to show in more detail.