Add opening the case to instructions.

Co-authored-by: Jake Howard <[email protected]>

Author: raccube

kit/brain_board.md

@@ -13,7 +13,7 @@ and controls the other peripheral boards.
 ### Flashing SD card
 
 In order to get access to the SD card, you will need to open up the case for the brain board. Pull the latch at the end of the case in order to hinge it open.
-The SD card is located on the underside of the board. Grab the SD card with your fingers and simply pull it out of the slot.
+The SD card is located on the underside of the board. Carefully open the Brain Board's plastic case, grab the SD card with your fingers and simply pull it out of the slot.
 
 To fully update your Brain Board's software, or refresh it if you think it's not working correctly, you can flash our SD card image onto the microSD card in your Brain Board.