First of all, here is a direct link to the ONLINE USER'S MANUAL for that model:
To view the Owner's Manual with Operating Instructions just use your mouse to click on the link, which is the underlined and highlighted text just above. This will open a new web browser page automatically for you and allow you to view the information at the website indicated or the contents of the Owner's Manual.
You may need ADOBE READER installed on your computer to read PDF documents. You can download this free at WWW.ADOBE.COM
if necessary. Click on the DOWNLOAD ADOBE READER button on right side of the ADOBE home page when you get there, and then just follow the onscreen instructions to install it.
See page 3 of the ONLINE USER'S MANUAL for detailed instructions on how to calculate the square root of a number.
Basically you just do the following:
Press the SECOND FUNCTION button (2nd),
Then press the SQUARE ROOT button (looks like a checkmark),
Then type in the number you want the square root of (say 25),
Then hit ENTER.
The answer should be 5.
Thank you very much and good luck.