In order to create a new folder from your File Manager, please go to your www folder and click Create New Folder (second link from top on the folder list). You will be prompted to type in a folder name at the top right corner of the page.
The procedure for creating a file is very similar - the respective link is the first after the folder list and precedes any valid filename. After clicking Create New File, you will again be prompted for a filename at the top right. Aside, below the filename you will be offered a choice of file types - if you do not feel sure what the file should be, please use the default option (Text Document) and click the Create button.
Upon successful completion your screen will be refreshed and a confirmation message will be printed at the top right corner of your screen.