subdomain for docs - folders not viewable

[drh2020]

I set up a subdomain called docs.<mydomain>.com and I wish to allow an ftp user to upload our organization's documents to several subdirectories.
I want to them to be visable under
http://docs.mydomain.com
and simply show a listing of the directories:

- newsletters
- agendas
- misc
..
without an index.html file.
Right now, because there is no index.html file the page defaults back to the centos apache default page.
I dont know where to make the change in plesk or a file to fix this.
Please help!