You can layer text and objects to create the appearance of depth on a page. You can then move objects higher (forward) or lower (backward) in the stack.
You can group multiple objects so that you can move, resize, and rotate them as a single unit. To avoid inadvertently moving, modifying, or deleting an object, you can lock it.
If you want to layer objects behind body text, you need to add a background object to the page, then position it behind the text.
Select an object then overlap it with one or more other objects.
In the Format 
sidebar, click the Arrange tab.
With the object selected, do one of the following:
Move an object one increment at a time: Click Forward, or click Backward.
Move an object to the very top or bottom of the stack: Click Front, or click Back.
Tip: You can open the Arrange controls in a separate window that you can move anywhere. Choose View > Show Arrange Tools (from the View menu at the top of your screen, not from the View menu in the toolbar). You can also add buttons to the toolbar for Forward, Backward, Front, and Back.
Group objects: Shift-click to select multiple objects, then Control-click one of the objects and choose Group from the shortcut menu.
Ungroup objects: Control-click the group and choose Ungroup from the shortcut menu.
Tip: You can add buttons to the toolbar for grouping and ungrouping objects.
When an object is locked, you can’t move, delete, or modify it in any way until you unlock it.
Lock: Select an object (or Shift-click to select multiple objects), then choose Arrange > Lock (from the Arrange menu at the top of your screen).
Unlock: Select one or more objects, then choose Arrange > Unlock.
Alternatively, select one or more objects; in the Format sidebar, click the Arrange tab; then click Lock or Unlock (near the bottom of the sidebar).
Tip: You can add buttons to the toolbar for locking and unlocking objects.
If you can’t select an object, it may be a master object placed on the page background. To edit it, you first need to make it selectable.