Enter your course and follow these steps!
1) Turn editing on
2) Choose the resource add a file
3) The screen will change.  Fill in the name of the file and a short summary.
4) Click the button "choose or upload a file"
5) You will see the file list in your course.  Because you want to add a file from your own computer, go down to the very bottom (if you have a long list, you will have to scroll) and find the button for "upload a file".
6) Browse to the file you want, click open, and OK
7) You will be returned to the upload screen and the path to the file will now be in the box
8) Click upload the file. After a bit, you will return to the file list and it will say "file uploaded successfully".
9) At this point, you have to CHOOSE the file.  Find the file you just uploaded and look all the way over to the right and click on the word "choose".  It will probably be blue.
10)  At this point, you have been returned to the resource window.  You will see the path to your file in the box.  Scroll all the way down to the bottom and click "save changes".