WordPress media library is a little bothersome to use. Uploads go into a /2013/07/folder, are stored in the wp_posts table and all sorts of thumbnails are created.
The shortcodes [
The File Manager gives you control over the assets folder and is a simple wrapper of filethingie by Andreas Haugstrup Pedersen.
To access it simply click Media > File Manager.
It will open a page like the one below, which can be used to upload / create folder / delete files.
Please note that overwriting isnt supported by filethingie so files need to be deleted first.
You can perform actions on a file by clicking the diamond next to the name,
Also, you can collapse the wordpress admin sidebar (left arrow at the bottom of it) if you like, to maximize the screen area.