Create folder
First select the folder in the tree below where you would like the new FOLDER to be created. Then give the folder a name and press the "Create Folder" button.
Upload a file First select the folder in the tree below where you would like the new FILE to be placed. Then browse to the file on your computer and press "Upload".
 
File Browser
Preview
First select a file from the tree menu to the left, then press the "Select" button.