Please be aware that as soon as you make your content live and available via a link to the public, it will become searchable by Google.
If you DO NOT want Google to index your content, be sure to set your Title/Folder to "Block search engines from indexing my content".
Google Webmaster Tools
First things first, you'll need to verify ownership of your Custom Domain with a DNS TXT Record.
If you have a custom domain with us, you've likely chosen a sub-domain of your existing website. If you ever need to remove a Google search result entry you must do the following in order to verify ownership of the site.
(1) Add your custom publishing domain as its own site on Google Webmaster tools
(2) You must verify you own the site by adding a TXT type DNS record to your custom publishing domain (sub-domain)
Requesting URL Removal Using Google's Tool
Once your Hub has been verified by Google Webmaster Tools, you can use the URL removal tool to request that Google remove already indexed entries from searches.
Requesting That Google Re-Index Your Content
If you make changes to your content, you may want to request that Google re-index your content to reflect any meta description updates. Click here to learn more about how to request Google to recrawl your Hub.