Yep, this is fortunately very simple - all you need to do is edit the file core/config.php and update the value for the hostname field to your new domain.
If you're looking to point a domain to your site, and you're using a web host, please contact them for assistance. If you're using a VPS/dedicated server, I tend to refer people to the Digital Ocean guides which I find to be very helpful: https://www.digitalocean.com/community/tutorials/how-to-set-up-apache-virtual-hosts-on-ubuntu-18-04
Once that's done, edit the Nameless file core/config.php and set the hostname value to your domain.
Your template is missing support for the Friends module - if you're using the default template, please ensure you correctly uploaded the custom/templates/DefaultRevamp/friends folder from the module, and if you're using a custom template please contact the template author for support.
You can try using a different browser - if the issue persists there should be a fix for "config unavailable" in the next release.