Loading the Solver add-in for Excel so that you can perform graphical analysis of charts

For starters, see here. For the quick start version, see here:

1. File => Options => Add-ins
2. Check "Active Application Add-ins" first to see if it's already loaded. If "Solver Add-in" is not in there, search under "Inactive Application Add-ins"
3. Near the bottom of the window, under the "Manage" drop-down, select "Excel Add-ins" and hit the Go button.
4. Ensure the "Solver Add-in" button is checked off, then click the "Ok" button and save all the way back to your workbook.