file “Not Found” after FTP upload

Complete newbie here, so help’s really appreciated. I can’t seem to figure out why URL links showing as “not found” after FTP upload. I’ve created a separate directory outside of WP that’s named “docs”, e.g.
Here’s URL for file:
http://www.911businessideas.com/docs/GoogleCheatSheet.pdf
URL: http://www.911businessideas.com
FTP app shows that file is on server, but URL doesn’t properly link. Where should I be uploading files that don’t need to be linked within WP?
WP is installed at:
/htdocs/wp….
Access to admin panel isn’t a problem & I can upload other content to the “wp-content/uploads”, but I don’t want to have these longtail URL’s to manage.
I’d like to add additional HTML pages as subdomains in future. Where would those need be placed?