I have no idea what to do

hi, i am very new to wordpress; so i really dont understand how to set this up.

https://blog.onoeart.com/

is my wordpress site.

i want to make that into https://www.onoeart.com

but when i go to general settings the blog url is gray; the link it provides me just confuses me even further!

i dont have anything in my ftp except for a few files; but no wordpress files. i really dont know what to do.