When you are adding or moving an Element, you can simply click any element and it will go to the lowest section of your Blast. If you have an Element you wish to be present higher up, you need to click and drag the Element to the location you would like in your Blast from the Elements panel.
While dragging the Element, you will see grey borders appear around the existing Elements. If you drag the Element over those borders, you will see a blue line appear. When you see this line, you can release the Element to drop it into that place in your Blast Editor.
Please Note: If you do not see the blue line appear before dropping the Element, it will NOT be added to your Blast or moved to the new location in your Blast. You are ONLY able to drop your Element where you see this blue line.
For information on how to Drag and Drop already added elements, check out this article here: How to Use Blast Elements