When you have several campaigns, it can be easy to get lost. Creating folders helps you organize the work better. Keep in mind that you have to be an Admin to create folders and to move campaigns into them.
Here is how you can add a campaign to a folder:
Access the "Campaigns" tab
In the left menu the "Folders" section will be visible
Click the "Create Folder" tab
After you have created a new folder, find the campaign you want to add to the folder
Click on the right drop down and move the template to the new folder.
You can also move templates into folders as follows;
Access the "Templates" tab
Locate the template you want to add to the folder
Click on the right drop down and move the template to the desired folder.