Turn your calculator on. Press the blue "2nd" key at the top-left of the keypad, then press the "0" key.
Press the "LN" key on the left-hand side of the keypad, then press the down arrow key located in the top right corner of the keypad to scroll down to the standard deviation option, labeled "stdDev(" then press "Enter". The "stdDev(" prompt will appear on the screen.
Press the "2nd" key, then press the "(", or left parenthesis key, located above the number "8" key to obtain the left bracket symbol "{". Enter the numbers, separating them with commas by pressing the "," key above the number "7" key. End the statement by pressing the "2nd" key then the ")", or right parenthesis key, to enter the right bracket, "}", then press the ")" key again to enter the ending parenthesis.
Press "Enter". The screen will display the standard deviation for your data.