Select “Mark Special” from the Time menu or click on the Mark Special button to bring up the Mark Special window

Select the category, client, project, and color combination of the time records you want marked from the pop-up menus on the right side of the window.  If you want to specify a date range for the Start Date, use the calendar.  If you don't want any time records marked that don't fit the specifications you've selected, check the box next to “Unmark others.”

You can now have the totals calculated by the specifications you selected here.  After clicking OK, click on the Totals icon in the Tool Bar so that Total Marked Indicator is visible (totals calculated from marked time records only). 

Tips on using the calendar.
• Click on a day to select it.
• Click on the year or month to advance the year or month.
• Hold down the option key to move backwards when selecting the year or month.
• Hold down the shift key and the year / month values change faster.
• Click on the days of the week (S M T W T F S) to display today's date.