I have a report layout, which is shown below:

I have set both parameter PackCode and MagCode to NULL (@PackCode = NULL , @MagCode = NULL).
Before I change the page break option to (Between each instance of a group) and the Group Expression (group on : [PackCode]), my report data only show one row but I execute my SP exec rpt_sp_list @PackCode = NULL , @MagCode = NULL and it have 2,000+ rows.
The requirement is I want to page break each PackCode data and it should be shown on a new page in SSRS. After export to excel, the excel sheet name should be each PackCode name. In future, there will be as much as PackCode.
How can I achieve this?
Thanks a lot.