Angelina Jolie

How do I calibrate my digital scale?

I recently got a Digital hand scale from a friend of mine, it just need calibration. It says “Digital Hand Scale” on the back. The buttons I have are “Tare” “Mode” and “On and Off”

Here are some pics

http://tinypic.com/view.php?pic=2wbyvqe&s=7

http://tinypic.com/view.php?pic=2qx5nvc&s=7

My friend said it might be a “digi weigh”? I dont know how to calibrate, I went to a shop. They said that I didnt have to use a weight of 500 grams, he told me to use a 50 weight?