The simplest assignment requires the upload of a single file.  The assignment will appear in your Moodle course as

assignment

with the text varying according to the assignment.  Clicking on this link will bring up the assignment interface

Student-Single-Assignment

The interface will give you some additional information on the assignment plus the dates when you can submit a file.  Clicking on the Upload a file button will bring up the upload dialogue

upload-dialogue

Clicking on the Choose a file button will bring up the File Picker that will allow you to select the file to upload. 

filePicker

In the File Picker, select the source of the file.

  1. Use Upload a file to load a file from your computer's disk. Click on the Browse button to find the file and then click on the Upload this file button.
  2. The GoogleDocs, Flickr public and Picasa web album links allow you to search these repositories for files.
  3. Moodle also maintains a list of recently uploaded files and other files on the system.  Given access restrictions most files on the system will be hidden from you.

Once that is done, click on Save changes to actually upload the file.  Your assignment interface would now look like

submitted-doc

If you hit the Choose a file button again, you will be replacing the current file.

Once you have the correct file loaded, click on the Save changes button.  Your assignment interface will now show the name of the file you uploaded and, if the instructor has set the assignment to allow it, the Upload a file button will have changed to Update this file which allows you to replace the file with a new one.

Remember that Assignments pass information between you and the instructor.  Uploaded assignment files are not visible to other students.