To allow directory listing or directory browsing in your Linux VPS, create a .htaccess file (Yes, it should be named as .htaccess without an extention). Insert this line: Options +Indexes
It can be done either with the following:
1. Using the File Manager in Plesk control panel (if your VPS has Plesk).
2. By logging in to the server through SSH and use your favoried command line editor such as vi.
3. Create the file from your local machine or your PC, then upload it to the server via FTP.