Redirecting from a landing page to another site

My company has taken over another business, I have created a landing page stating this on the taken over site with a link to our business site but how can i redirect automatically with a 5 second delay? I have tried to use the URL mapping code provided but it doesn't work how I need it to..

Add this code to Landing Page Header

<script>
         setTimeout(function(){
            window.location.href = 'https://google.com';
         }, 5000);
</script>