To edit the size or alignment of your Elements individually, go to the Design Tab and click on one of them. A small window will pop up with the different options available to modify it.
Remember that you can change the text styles on the content editor, more details over here 😉
3"Big things come from small ideas" 😎
To revert all changes made on an Element, click on the Reset Position button.
You can also Drag & Drop your Elements within the slide.
Use the grid to align and position your Elements when dragging them. The grid will only be visible when moving the Element around.