You would need to use the phones File Manager app, if it has one, and if it doesn't, you can download one.
You can also connect the device to a computer via a USB cord and move all the files at once, rather than one at a time, to the card this way. It also allows you to have a back up on the computer. Then you will need to go into your gallery app and set it to vie the card for photos. Lastly you may want to set your camera apps settings (or whatever using to take photos) to save directly to the card.