How to delete a Layer: Bottom left photo shows the trash can in the upper right of photo. First make sure whatever layer you want to delete is selected (make sure the layer has anchor points). Then click on the trash can to delete. If you don't want to delete and you just want to undo your last edit, the counterclockwise arrow at the bottom left of the screen will undo it.
How to duplicate a Layer: Once you select a Layer (anchor points will show up around it), a menu bar will appear. In the middle photo below the menu bar shows additional items (size, opacity, arrange, etc). To the right of the text 'Arrange' is a 'duplicate' icon (it looks like one box overlapping another). When you click on that duplicate icon, another layer of the item you have selected will appear and you can then edit it, resize it or move it.
How to move a layer behind or in front of another layer: Each text, photo or shape represents a layer on your canvas (product). As you are creating your sign you may want to move a layer behind another layer. In order to do this, you have to first select the layer you want to move. Once anchor points are around the item, a new menu bar will appear at the top of the screen. Click on the 'Arrange' text and another box will pop up with numerous choices. The small black and white squares indicate which level you want to move your layer (back to front, front to back, send to front, send to back). Click on those icons to move your layer.
How to make text or photo an exact size: You may be under restrictions to have a certain size text height. If that's the case, it's easy to make any item an exact size. The photo below on the right shows a menu that pops up once you select an item and then click on Size in the menu bar. You can see the current size of the text. If you want it to be an exact height or width, just change the numbers to your preferred size.