Public websites in SharePoint 2013

We had a consulting firm set up our SharePoint 2013 infrastructure but they are too expensive to use on a long-term basis. Our content is basically an Intranet governed by Active Directory accounts but we now need to expose some but not all of that content to the public using Anonymous Access. I'm thinking that one way to achieve this might be to extend the current web application into the Internet Zone using a different URL? I realise that there's nothing particular about the name "Internet" in the zone context but it seems the most logical to use? Under our current site collection we have a number of sites and sub-sites and more than one of those sites/sub-sites needs to be exposed to the public. For example under our Team site we have an Education site and a sub-site for Pre-Edition Training with a URL like this --> https://sp.xyz.net.au/edu/pre-edition-training/SitePages/Home.aspx. I only want to make the Pre-Edition Training site available to the public with anonymous access. I also have another site under the Team site called Chronicle. I want to make this site available to the public with anonymous access.

Can I put each of these into their respective Internet zones, give them a different URL and assign them anonymous access? I've read some articles but am struggling to understand exactly what to do here and whether I can do all this through Central Administration or whether I need to use PowerShell to achieve any of it. I'd prefer to use a SharePoint interface rather than PowerShell if possible.

Any help or references to resources that tell me how to do this would be greatly appreciated.

Thanks

Peter