How do I undo/redo?

You can undo and redo elements on the page by clicking on theor buttons at the top of the page in the toolbar.

Another option for undoing and redoing actions is:

On a Mac computer:

⌘ + Z = undo

⌘ + shift + Z = redo

On a PC computer:

ctrl + Z = undo

ctrl + shift + Z = redo