you can just connect over FTP with your user, navigate over to the mysite.com directory, and create a new one inside that called “subdomain” or whatever you need it to be. but i don’t recommend using it for separate software installations if /mysite.com already has something installed there
yes, my wordpress site is installed in the main domain, no blog folder so I can’t use the mysite.com/subdomain format?
That’s not a configuration that we recommend. When configured to use “pretty” permalinks, WordPress attempts to handle all requests under its directory. While it’s possible to “carve out” a subdirectory that it should leave alone (e.g, for stats), doing so is fundamentally messy and sometimes unreliable. It’s much easier and cleaner to set a second application up on its own domain (e.g, subdomain.mysite.com).