This is a quick guide on how to create your own holding page for a Plesk based hosting server.
Firstly, you need to create your holding page using your HTML editor of choice. Then, using your copying method of choice, log into your Plesk server and copy that index file, along with any associated CSS / Images to:
/var/www/vhosts/.skel/0/httpdocs/
(The existing index file is named index.html, so if your index file is a .htm or .php file, be sure to remove the existing file to avoid conflicts.)
Any new domains created on the server will use the files inside that folder as the base files for all new hosting accounts.
Please note, if you have domains with old style hosting pages already set up on your server, you will have to manually copy your new holding page into those accounts if necessary. The contents of the skeleton folder will only apply to hosting accounts set up from that point.