I have to redirect page if the user entered page name in URL. I have two pages called as index.php and next.php

In index.php page there is a link called <a href="next.php">Click here</a>. If i clicked on link then page is redirecting on next.php properly.

Now the issue is if any user directly entered next.php on URL then the page should be redirected on index.php page. That means the user will not able to access directly next.php