I’ve edited your post for readability. When you enter a code block into a forum post, please precede it with a separate line of three backticks and follow it with a separate line of three backticks to make it easier to read.
You can also use the “preformatted text” tool in the editor (</>) to add backticks around text.
When it says your (a) element should be nested within your p element it means the <a href="url"></a> should be within the opening <p> and closing </p> tags.
And the hint says:
After nesting the anchor ( a ) element, the only p element content visible in the browser should be Click here to view more cat photos. Double check the text, spacing, or punctuation of both the p and nested anchor element.