Creating Subfolders on Server Space

Can I create subfolders under public folder on the server? If yes, Can someone guide me . I could not find it on the tutorials.

The Server Administration guide, section "Web File Manager":

Note that in the current version it’s not possible to create or delete folders through the Web File Manager. Necessary folder structure should be created on the server in a regular way – e.g. using Windows Explorer.

I believe it answers your question: yes, it's possible, but not through the web interface.