Create a Detail Page - Step III
27. Highlight Return to List and then click Modify > Make Link. In the Select File window, click on listBy.asp and then click on the Parameters button.

28. Type CategoryID in the Name column of the Parameters window and then click on the Value column to expose the lightning bolt symbol. Click on the lightning bolt symbol.

29. Click on CategoryID in the Dynamic Data window and click OK.

30. Click OK in the Parameters window.

31. Click OK in the Select File window.

32. File > Save and you are done with the detailPage.asp!
Get an example of the page here.