File Manager & Tools:

Any time you need to pick an image or a file in concrete5, we use the File Manager.
You see it from various blocks when you need to pick/add assets and you can get to it from
Dashboard > File Manager as well.

The File Manager just manages assets you're going to use in your website,
it's not an alternative to FTP or a way to put files on your server in specific directories.

Instead the File Manager actually chooses where to put files on its own so it doesn't accidentally over-write anything, and it also creates records in your database about the assets so it can manage versions, permissions, and interesting meta data.