Financial Designer question

How do I change a line item in my P&L so that expense is calculating against the proper income?  My Gift Shop expense (for actual, budget, MTD and YTD) should be calculating only against the Gift Shop revenue line item to get cost %.  But it appears that currently this is not happening.  How exactly do I make this change?  I know I go under Maintenance in Financial Designer, but I'm having a problem on what to do next.  Thanks for any input.

Maintenance-Financial Designer-Layout-Select the report-Edit then Right-click on the % column-header and click on the % calculation option. Go to the Edit tab and select the expense you want from the left window and the revenue you want from the right window, click Append, never click on Replace. Save. Do the same for your other % columns or copy from this one.

Thank you, John!  I greatly appreciate your direction. I've now been able to correct all of the % calculations for our Gift Shop revenue.  Again, thanks very much.

Thank you for posting this! I was able to use it for the same purpose.