A folder is used to organise information within an Interact site. It may be indicated by a icon. When you click on a folder link you will just see the components that have been added within that folder. This may be displayed down the page, or you may see a navigation bar across the top of the page, depending on how the site administrator has set the folder up.
If there is a navigation bar across the top of the folder, then you will also see 'Next' and 'Previous' links at the bottom of the page which you can use to move through the content of the folder.