I have a 1530 which is very similar. When you turn on the machine, select the straight stitch, then move with the ball over to the top right where the number 0-5 is located. 2.5 is center. So move the mouse to where you want the needle to move to below the number and press the OK (indent on the side) button. You should see the needle move. PM if you have any further question.
I did Google the Bernina model and found a short u-tube video and a few places to get the manual.
https://www.google.com/search?q=BERN...utf-8&oe=utf-8