Storage
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 gray-colored.
SD CARD
Total space: Displays the total amount of your external memory.
Available: Displays the amount of space available in your external memory.
Mount/Unmount SD card: Allows your phone to recognize your microSD card and release it to safely remove your microSD card.
Erase SD card: Erases all of the data stored on your microSD card.
Tap the Menu icon 
(at the upper-right corner of
the Storage screen) to access Display in MB (or GB) and USB PC connection.