sftp access - which folder?

Hello, i set up a linode server and set up a joomla cms page. All is working fine - but i need to access on file level.

As i log in as root user, i can access with the program filezilla … but there were so many folders.
In root or home, i did not find the files of joomla … investigating for a longer period … i did not find.

So please - where are the files of a page (setup done from linode) located - in which folder / subfolder?

Thank you!