I have a multisite install on digitalocean (nginx, mariadb stack). I tried activating the domain mapping plugin and it automatically took my site down. I quickly delete it. This was before I'd even configured it. I want to map a sub domain (e.g., http://artist1.mysite.com ) to a custom domain (www.artist1.com). I read the documentation around the plugin but it seems to be gear toward cpanel. I don't have cpanel on my server and I'm not sure how to proceed. Can you advise? Please be as detailed as possible. This is a new area for me and I'm learning as I go.