While working on your project, you may discover that you need to take a few steps back and undo the last few changes you've put in place. Picaboo has an Undo button that will revert your project back to the state it was in prior to the very last change you made. You can use the Undo option multiple times to Undo multiple changes, one at a time.
The Redo button will repeat all those steps that you recently undid, one at a time.
You can find these buttons in the upper right of your screen