We can currently add domains to our free hosting package, but each domain creates a new website.
I was wondering if there was a way to link multiple domains to a single website.
If I understand what you're asking, I believe you have to redirect your domains to the actual website domain.
In other words, if you have yoursite.com but also want yoursite2.com to go to the same site as yoursite.com you would just make the second domain redirect to the first domain.
Hopefully that makes some sense to you.
Maybe just use 301 redirects to your main one or something?