On this page there is a DIV element which hides part of the page. After 15 seconds this DIV element will disappear to make the page visible.
This DIV will disappear after 15 seconds
The HTML code for this example (if you use Gutenberg, you need to switch to HTML editing):
[timed-content-client hide="0:15"]
<div style="position:absolute;left:0;top:0; z-index:1000;width:100%;height:50%;background:#000;color:#ff0;padding:2em;text-align:center;font-size:2em;box-sizing:border-box;">This DIV will disappear after 15 seconds</div>
[/timed-content-client]