When editing events, there is a convenient "View on Frontend" button that allows you easy access to the frontend view of your event. One thing to keep in mind is that this will open the frontend event in a new tab.
Once you make changes on the frontend, you MUST refresh the original tab showing the backend for those changes to appear. Otherwise, your browser is stuck "in the past" and will not know that those changes have been made.
For a closer look, please watch the following video: