With the advent of Layout Builder as a means of creating easy, robust, well-designed pages, it understandable users will immediately look to how to use this for their site's homepage. But, as you'll quickly discover, the homepage provided out-of-the-box doesn't permit the use of Layout Builder since it's not a "regular" page; it solely relies on global blocks to build its content. The good news is that this is an easy change and only requires the person to have the Site Manager role to accomplish it.
It's not common by any means, but in certain circumstances, it is possible to seemingly--or actually--delete your homepage. Even though the few seconds after discovering this occurrence might give you a sense of panic and cause you to break out in a cold sweat, a simple solution is available to help you fix the situation.
