To restore an entity to a previous version, or to otherwise view the entity's edit history, focus your attention on the toolbar near the top of the view. Find the button labeled history and click on it. When clicked, a popup will appear displaying all recorded changes to the entity.
When the entity's history popup is open, you can scroll through the history and see any changes that were made, when they were made, and who made them. You can leave without making any changes by clicking the Ok button, but if you would like to restore the entity to any of the versions displayed in the popup, click on the button labeled Revert next to the latest modification that you would like. Upon clicking that button, the entity will restore to the state at the time of that change and refresh the page.