ssrs 2008 r2 use parameters for sorting purposes

In an ssrs 2008 r2 report, I have a report where a user wants to sort a report based upon the following parameters:
   1. lastName,
   2. firstName, 
   3. studentNumber,
   4. [School Name].
The above is the default order of how the user wants to be able to sort the report.

The following is the definition and the columns that are to appear in the report:
         studentNumber varchar(15)
 ,lastName varchar(40)
 ,firstName varchar(35)
 ,[School Name]  varchar(40)
 ,[School of Assignment] CHAR(3)
 ,grade varchar(4)
 , Description varchar(50)
 ,[Beginning Date] smalldatetime
The above columns are all contained in one tablix.

The user wants to be able to sort the report by changing the parameters that I just listed
above.

Thus can you show me code and/or point me to a url that would show me how to allow the user to sort
the report in any order based upon the 4 parameters listed above?