On the left side you see a hierarchical list of all folders in your mailbox. Folders can be used to file email messages by topic, sender or whatever you choose for organization.
Incoming messages usually appear in the Inbox folder which is the first item in the folders list. There are some special folders which are used by the system to store sent (Sent) or deleted (Trash) messages and where not-yet-sent message drafts (Drafts) are saved. These system folders are indicated with special icons.
The number of unread messages in each folder is displayed at the right border of the folders list.
Click a folder in the list to show the contained messages in the messages list on the right. The currently selected folder is highlighted in the list.
In the footer of the folders list, the Folder actions icon shows a list of folder-related actions when clicked. Most of the actions in the menu affect the currently selected folder.
This action will compress the folder size by finally deleting messages that have been marked for deletion.
This will delete all messages in the selected folder permanently. Be very careful with this operation as it cannot be undone. For security reasons, this action is only available for the Trash and Junk folders.
This menu item will take you the settings section when you can manage the mailbox folders. This is where you can create, delete, rename or re-organize your email folders.