Lets use the following terms for a simple card sort example.
Each of these terms will be written on a different index card and will be given to the people who are participating in the card sort. You can than ask people to organize the items into different categories. After people are finished organization the content into categories it is time to ask them how they would name each category. At this point you will want to give the participants some blank index cards and ask them to write down the name of each category on one of the index cards.
Using the items listed above a group of people might organize the terms into the following categories.
After the index cards have been arranged into different categories you will have the opportunity to talk with the participants about why they put items into certain groups. This is your opportunity to find out several different things from why things were grouped together in a certain way to understanding why a term was confusing. In talking to participants you may find that you need to rename or remove certain words to make it easier for a person to locate the information that they would be searching for in a website.