Very easy. Look at the steering like a clock. Your hands should either be in the 9-to-3 or 10-2 positions. Meaning your left hand will be on 9/10 and your right on 3/2. Since you're suppose to have both hands on the wheel, these are the ideal positions that they should be in.
Although I'm very bad at not doing this. My positions usually consist of: 1, Right hand at the 3 o'clock position with arm resting on window sill and left hand resting on gear stick. 2, Hands at 5-7 positions and arms resting on lap. 3, both hands resting on my lap and only steering with my thumbs and index fingers (only done when I'm driving on the motorway since there's little need to steer) It's bad habits. Don't do them.