PHP. redirecting to home page if GET parameters are not correct
<p>I am suppose to get these done, but not understanding how :| I'm a beginner in PHP, help me out!</p>

<p><strong>Implement the Profile page</strong>
 Create a file called profile.php.</p>

<p> Use a $GET Parameter ( userid ) to fetch the user details from the
database. If the GET parameters are not correct redirect him to home-
page.</p>

<p><strong>Implement profile pic feature in the profile page.</strong>
*<em>HINT:</em>* <em>Add profilepic column in the users table to store image name. And
create a folder called images in the current project folder to store all the
images. So when user opens profile.php fetch the picture name from the
database &amp; use HTML tag  to display the image</em>.</p>

<p><strong>Display posts by users on their respective profile pages.</strong></p>
