Move from domain to sub-domain and redirect

I am using Digital Ocean to host Ghost and it was originally setup at I want to move Ghost to sub-domain ( and setup the redirect as well. I am stuck here

It says that the directory is incorrect while in the same pic it shows that it is correct directory. What is the issue?

Note: I’ve made changes to Digital Ocean so that when someone goes directly to the sub-domain, they can see the blog and it works perfectly well. I want the people going to the domain to be routed to the sub-domain.

It can be useful

Okay you need to cd in that directory
something like

cd /var/www/

& to change the url follow url