To organise folders and files on a computer you must first open Windows Explorer. This is a program available on all computers running Windows (on Windows 8 it has been renamed File Explorer and the layout has been changed though the principles are the same).
There are a number of ways to open Windows Explorer depending on your computer but on Windows 7 you should be able to click on the Start button (in the bottom left corner of your screen) and then click on either "Computer" or "Documents" in the right hand side of the panel which opens up. This will then show a window similar to:
On the left hand side of this screen (the Navigation Pane) you can see a list of all folders on your computer. You can use this to see the structure of your filing system. If you click on the little arrow to the left of a folder name it will expand (or contract) to show (or hide) the sub-folders under that folder. (If there is no little arrow then there are no sub-folders.)
If you click on a folder name in the Navigation Pane then it will open the folder and display the contents in the right hand pane. You can see which folder you are looking at and where it is in the hierarchy by looking at the top of the window. In this example we are looking at the Utilities folder which is contained in My Documents which is itself contained in Documents.
To create a new folder, click on "New folder" at the top of the window. This will create a new folder called, helpfully, "New Folder". You can rename this to something more useful if you immediately, ie while the name is highlighted, type in a name for this folder and press "Enter". [You can rename a folder at any time by selecting "Organize", clicking on "Rename" and then typing in the new name as before].
To delete a folder, click on it, click "Organize", and then click on "Delete".
Click on More about files to see what else you can do.