Introduction
Not much to add here as its the same as an older post:
https://ip-life.net/how-to-auto-redirect-apache-default-webpage-to-a-specific-page/
Fix
The only difference required in CentOS is to actually make the index file in the /var/www/html/ location:
# touch /var/www/html/index.html
Then modify as per the old post to your requirements!
Voila.
How to Auto Redirect Apache Default Webpage to a Specific Page CentOS