Upload your files to the htdocs directory but don't specify the directory when requesting the content.

Use the following schema to form the URLs:

http://<storage name>.<hostname>/<file name>

Storage name and hostname can be found on the Storage tab -> Storages -> Details.

Example

Path to the uploaded file in the storage: 

sftp://4505-test@ams.origin.gcdn.co:2200/export/home/4505-test/htdocs/picture.png

Storage name:

4505-test

Hostname:

ams.origin.gcdn.co

URL to request the file from the storage:

http://4505-test.ams.origin.gcdn.co/picture.png

SFTP storage works only via HTTP protocol.