To install a microSD card:
1. Remove the battery cover and battery.
2. Slide the card holder in the direction of arrow to unlock it.
3. Raise the card holder with your finger.
4. Insert a microSD card into the holder. Make sure to check the position of the gold terminals.
5. Replace the card and card holder and gently press them, and then slide the holder in the direction of arrow to lock it.
6. Place the battery back into its compartment and replace the battery cover.
You can find a diagram on page 155 and 156 of the user manual. Download the manual from the Kyocera Hydro page.