Use the Storage menu to monitor the used and available space in your phone.
INTERNAL STORAGE
Total space: Displays the total amount of space in the phone’s memory. It’s listed in Gigabytes and also on a colored bar graph with a color-coordinated list of the apps as well as the amount of space they use. Remaining memory space is grey-colored.
SD CARD
Total space: Displays the total amount of memory space on the microSD card. It’s listed on a colored bar graph and in Gigabytes.
Mount/Unmount SD card: Mounts and unmounts the microSD card from your phone so that you can format the card or safely remove it. This setting is dimmed if there’s no microSD card installed, if you’ve already unmounted it, or if you’ve mounted the microSD card on your computer.
Erase SD card: Permanently erases everything on the microSD card and prepares it for use with your phone.