Your Samsung Galaxy S3′s storage can be expanded, you can expand the storage of the Galaxy S3 device device by using a Micro SD Card. You can insert or remove the Micro SD Card by following below mentioned steps.
1. First turn off the Galaxy S3 device.
2. Now remove the rear cover of the Galaxy S3 device.
3. While viewing the rear of the Galaxy S3 device, locate the SD Card slot on the right side above the battery compartment.
4. Now to insert the SD Card, slide it into the slot with the connectors pointing downward toward the screen. You should hear the card “click” into place. Also if you wish to remove the SD Card from Galaxy S3 device, push the card into the slot. It should “click” and eject from the slot.
5. Now you are done with the SD Card, place the rear cover of the Galaxy S3 and turn on your Galaxy S3 device.