This option allows you to know how to Setup your CDN storage folder, you can go through this video to know how to set it up 

This video will put you through on how to setup CDN storage:

You can also go through the steps below

• Login to the Admincp

• From the left menu, click on “Settings”

• Click on “CDN Storage”

• Turn ON the “Process Uploads”
• Turn ON the “Keep Files”
• Then click on “Save Settings” to save your settings