You want to follow this format:

I.    Main point to develop

   A.   Subtopic of that main point

   B.    Subtopic of that main point

     1.    Supporting reason

     2.     Supporting reason

             a.  Example

              b.  Example

                         i.  Explication or analysis of example

                        ii.   Explication of analysis of example

Some points to remember:  You can't subdivide any level of the outline into just one, because then you're not really breaking it down. Think of it as trying to cut a loaf of bread into one piece; it can't be done.    Therefore, if you have an A, you must have a B; if you have a 1, you must have a 2, and so on.  Obviously, you can go beyond the two and go into three and four.  This sample above is just to serve the purpose of showing the breakdown, but of course you can break down the A into 1 and 2 and so on as well.  Also, you should not have any complete sentences; an outline should consist of guiding notes to help you later in developing paragraphs. Good luck! Feel free to ask any additional clarifying questions if you're having trouble with this.