If your SD card, USB drive, or any other storage device is not shown, find and select the appropriate folder(s) here. You may also hide any folders which you do not wish to display. Note that if you select any folders for which you don't have read access, they will not be displayed, but will remain selected here. This is to allow for items which are not always connected, such as hard drives.
You may also select any additional folders if you wish - but be very careful selecting, and in particular manipulating, any system folders.
Bold items are mount points. The majority of mount points are related to the system and not important to users, but SD cards and other storage devices should each have a mount point.
Italic items indicate that the folder could not be found. This can occur when a mount point, or a previously selected folder (such as a removed SD card) exists at or below that point in the file tree. The item will be Bold and Italic if it is a mount point which can't be found in the file system.