When you are working in Performance Monitor, in the "Add Counters" dialog box, and need more information about a particular counter, what should you do?

click and check show description checkbox

Explanation:

The Add Counters Dialog box enables monitoring for the processor, logical disk, memory, physical disk and network interface. While these items will be listed on the dialog, if you need to get more detailed description of a particular counter, you will have to click on the show description check box.