Report Designer - Table datasource

Hi everyone! First of all I'm sorry for my English...I know that is opprobrious xD
I have a questions about a Report that I'm trying to build with "Pentaho Report Designer - Version 5.0.1".

I want to reproduce the report that you can find in the menù help options at the voice "Sample Reports --> Advanced --> JDBC Custom Data Source" ;
in simple terms what I need is a Report that when I pass 2 (or more) parameters, the query select the matched columns in the database and show the records on page.

For example:
I have a database with one table 'Users'; the columns are 'Name, Surname, City, Age'.
If I select the page name and surname I will see all related records. The same if I select the name and city ... and so on.
How can I do that?

Until this moment I have tried to copy the example that I mentioned before, with poor result.
I used a table data source and I have defined inside all the columns that is possible to show and two 'drop down' parameters that select the relative column.
If that's is correct I don't know where I can take the field to insert on page! Because they aren't defined on the Data Tree (as if I have defined a static query).

I hope I was clear enough :)
Thanks in advance for the answer!!

Massimiliano