Select the option Segments from the Lists dropdown. This will open the Segments section.
Click the Create New Segment button.
Now, select the option to create a segment from a campaign.
Then, enter the segment title and select the campaign upon which you would like to base the segment.
Click the Next button to continue.
Once you have selected a campaign, you need to filter out subscribers you wish to include. To do that select a match type (condition) and a data point against which you wish to match subscribers. You can segment them by email, first name, last name, or any custom field you have added to the list. Also, another option is to filter contacts based on their activity.
For more information about Subscriber-based and Activity-based filters, see the support topic How to Create a Segment.